Optical sensor module

Abstract

The invention relates to an optical sensor module. The present disclosure provides a substrate assembly for an optical sensor module. An example substrate assembly for an optical sensor module includes: a light emitting device mounted on a first region of a substrate; a metal shield assembly including a first metal shield assembled to the substrate over the first region; and wherein the first metal shield comprises a first opening providing an optical path for light emitted by the light emitting device, the first opening being dimensioned such that the light emitting device can be inserted inside the first metal shield through the first opening.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATION(S)

[0002] This application claims the benefit of priority to French Patent Application No. 2311593, entitled “Module de Capteur Optique,” ​​filed on October 25, 2023, which is incorporated herein by reference to the maximum extent permitted by law. Technical Field

[0003] The present disclosure relates generally to optical sensors, and more particularly to optical sensor modules. Background Art

[0004] Optical sensors, such as proximity sensors, can be used to detect the presence of nearby objects. Optical sensors can do this without physically contacting 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 to such nearby objects. Optical sensors can be used in various electronic devices, such as cameras, phones (including smart phones), smart watches, tablets, vehicles, machinery, and other devices for detecting the presence of nearby objects and / or the distance to nearby objects. After detecting the presence of a nearby object, the electronic device can be configured to perform a function, such as moving a mechanical feature to a safe position, transmitting an alarm signal, coupling or decoupling electrical communications, or any other desired function.

[0005] An optical sensor generally includes components such as a light emitting device, a light receiving sensor, and a processing device generally for processing signals received from the light receiving sensor. The components of the optical sensor may be formed on a substrate, and a cap may be bonded to the substrate over the components, for example to protect them from damage, thereby forming an optical sensor module, also referred to as an optical sensor package. The cap is generally formed with a first cap opening over the light emitting device and a second cap opening over the light receiving sensor.

[0006] Generally speaking, the light emitting device emits a light signal, such as through a first cap opening. If an object is outside the optical sensor module and sufficiently close to the optical sensor module, the light signal may be reflected by the object toward the light receiving sensor, such as through a second cap opening. The light receiving sensor may then generate an electrical signal indicative of the received light signal, which may be transmitted to a processing device to process the received light signal, such as to determine the presence of a nearby object and / or a distance to the nearby object.

[0007] There is a need for improvements in optical sensor modules, particularly to address electromagnetic interference (EMI) issues between an optical sensor module and another electronic device (e.g., an electronic device incorporating the optical sensor module), which may be designated a host device, particularly for optical sensors used in consumer electronics products. For example, the host device may be a camera, a smart phone, a smart watch, a tablet, or another device for which detecting the presence of and / or distance to nearby objects may be useful. Summary of the invention

[0008] One embodiment addresses all or some of the disadvantages of known optical sensor modules.

[0009] One embodiment provides a substrate assembly for an optical sensor module, the substrate assembly comprising:

[0010] - a light emitting device mounted on a first area of ​​the substrate;

[0011] - a metal shield assembly comprising a first metal shield assembled to the substrate over the first region;

[0012] The first metal shielding member includes a first opening, which provides an optical path for light emitted by the light emitting device. The first opening is designed with a size such that the light emitting device can be inserted into the first metal shielding member through the first opening.

[0013] In one embodiment, the first metal shield is dimensioned to surround and at least partially cover the light emitting device, the first metal shield, for example, includes side walls joined by a top wall, the top wall including a first opening.

[0014] In one embodiment, the light emitting device comprises:

[0015] - at least one light source, the first opening providing a light path for light emitted by the at least one light source and being dimensioned so that the at least one light source can be inserted into the interior of the first metal shield through the first opening and mounted on the substrate; and, optionally,

[0016] - a photodiode configured to monitor the light emitting device, the first opening also providing an optical path for light transmitted to the photodiode and being sized so that the photodiode can be inserted into the first metal shield through the first opening and mounted on the substrate.

[0017] In one embodiment, the substrate assembly further includes a driver mounted on the first region of the substrate, the driver configured to control the light emitting device.

[0018] In one embodiment, the first opening extends above the driver.

[0019] In one embodiment, the first metal shield is electrically coupled to the substrate, such as to a ground trace of the substrate.

[0020] In one embodiment, the metal shield assembly also includes a second metal shield assembled to the first metal shield and at least partially covering the first opening, the second metal shield including at least a second opening that allows light emitted by and / or transmitted to the light emitting device to pass through, the second metal shield being, for example, electrically coupled to or in contact with the first metal shield.

[0021] In one embodiment, the second metal shield includes a recessed portion extending into the interior of the metal shield assembly.

[0022] In one embodiment, the second metal shield seals the first opening.

[0023] In one embodiment, the second metal shield at least partially closes the first metal shield.

[0024] In one embodiment, the metal shield assembly includes an absorbent layer positioned on an inner surface of the metal shield assembly facing the light emitting device, such as positioned on an inner surface of the first metal shield facing the light emitting device.

[0025] In one embodiment, the substrate assembly further comprises glass assembled to the first metal shield over the first opening, the glass comprising an electrically conductive trace, for example electrically coupled to or in contact with the first metal shield, such as coupled to a ground trace of the substrate through the first metal shield.

[0026] In one embodiment, the metal of the metal shielding assembly is selected to reflect and / or absorb electromagnetic waves, for example the metal is copper, a copper alloy, stainless steel or any conductive material that also has a relative magnetic permeability higher than 1.

[0027] One embodiment provides an optical sensor module, comprising: a substrate assembly, such as the above-mentioned substrate assembly; and a module cap assembled to the substrate and adapted to at least partially cover the metal shield assembly and components mounted on the substrate.

[0028] One embodiment provides a method of manufacturing a substrate assembly for an optical sensor module, the method comprising:

[0029] - assembling a first metal shield to the substrate over a first region of the substrate, the first metal shield comprising a first opening providing an optical path for light emitted by a light emitting device to be mounted on the first region; and

[0030] - Mounting the light emitting device to the first area through the first opening.

[0031] In one embodiment, the method further comprises, after the mounting step, assembling the glass including an electrically conductive trace to the first metal shield over the first opening, the conductive trace being, for example, electrically coupled to or in contact with the first metal shield.

[0032] In one embodiment, the method further includes, after the mounting step, assembling a second metal shield to the first metal shield so as to at least partially cover the first opening, the second metal shield comprising at least a second opening that allows light emitted by and / or transmitted to the light emitting device to pass through, the second metal shield being, for example, electrically coupled to or in contact with the first metal shield. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The foregoing features and advantages, as well as other features and advantages, will be described in detail in the following description of specific embodiments given by way of illustration and not limitation, with reference to the accompanying drawings, in which:

[0034] Figure 1A is a three-dimensional view of a substrate assembly of an optical sensor module according to an embodiment;

[0035] Figure 1B yes Figure 1A a cross-sectional view of a substrate assembly;

[0036] Figure 2A , Figure 2B , Figure 2C and Figure 2D This is an example of manufacturing Figure 1A and Figure 1B A top view and a three-dimensional view of an example of a method of substrate assembly;

[0037] Figure 3A is a three-dimensional view of a substrate assembly of an optical sensor module according to another embodiment;

[0038] Figure 3B It is shown Figure 3A A cross-sectional three-dimensional view of details of a baseplate assembly;

[0039] Figure 4 is an example for manufacturing Figure 3A and Figure 3B The substrate components of FIG. 2A to FIG. 2D 3D views of variations of the method;

[0040] Figure 5A is a three-dimensional view of a substrate assembly of an optical sensor module according to another embodiment;

[0041] Figure 5B It is shown Figure 5A A cross-sectional three-dimensional view of details of a base plate assembly;

[0042] Figure 5C yes Figure 5A A three-dimensional view of a variant of a base plate assembly;

[0043] Fig. 6A and Figure 6B is an example for manufacturing FIG. 5A to FIG. 5C The substrate components of FIG. 2A to FIG. 2D Top view and three-dimensional views of variations of the method;

[0044] Figure 7 is a three-dimensional view of a substrate assembly of an optical sensor module according to another embodiment; and

[0045] Fig. 8A and Figure 8B is an example for manufacturing Figure 7 The substrate components of FIG. 2A to FIG. 2D Top view and 3D views of variations of the method. DETAILED DESCRIPTION

[0046] Similar features in the various figures are denoted by similar reference numerals. In particular, common structural and / or functional features in various embodiments may have the same reference numerals and may have the same structure, size, and material properties.

[0047] For the sake of clarity, only operations and elements that are useful for understanding the embodiments described herein are illustrated and described in detail. In particular, not all components of the substrate assembly are described in detail, and the embodiments are compatible with common substrate assemblies in optical sensor modules. For example, the light emitting device, the light receiving sensor, and other components of the optical sensor (such as a processing device or circuit) are not described in detail. Similarly, not all components of the optical sensor module are described in detail, and the embodiments are compatible with common optical sensor modules.

[0048] Unless otherwise stated, when referring to two elements being connected together, this means a direct connection without any intervening elements except conductors, and when referring to two elements being coupled together, this means the two elements may be connected or they may be coupled via one or more other elements.

[0049] In the following disclosure, unless otherwise stated, when reference is made to absolute position qualifiers (such as terms "front", "rear", "top", "bottom", "left", "right", etc.) or to relative position qualifiers (such as terms "above", "below", "higher", "lower", etc.) or to orientation qualifiers (such as "horizontal", "vertical", etc.), reference is made to the orientation shown in the accompanying drawings, or to the substrate assembly or optical sensor module as it is oriented during normal use.

[0050] Unless otherwise stated, the expressions "about", "approximately", "substantially" and "around" mean within 10%, preferably within 5%.

[0051] In the following disclosure, unless otherwise stated, when reference is made to glass, this includes elements made of materials that are relatively transparent to light at the wavelengths used (e.g., 90% or greater transmittance to those wavelengths). This includes, but is not limited to, glass materials or plastic materials. Glass may be formed from a solid single material, or may be formed by combining multiple materials, in which case only a portion of the glass may be a transparent material. Glass may include, or consist of, a lens or multiple lenses and / or an optical filter.

[0052] In the following disclosure, unless otherwise stated, when a conductive element is referenced, reference is made to an electrically conductive element.

[0053] In this disclosure, unless otherwise stated, when a component is referenced, reference is made to an electronic part.

[0054] 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 having a combined function (e.g., a combination of at least two of the above-mentioned modules) or other functions (e.g., a combination of a proximity detector module with a floodlight and / or a dot projector).

[0055] Embodiments relate to optical sensor modules. An optical sensor typically includes a light emitting device, which includes, for example, a light emitting diode (LED) or a laser such as a vertical cavity surface emitting laser (VCSEL), and a light receiving sensor, which includes, for example, a photodiode or multiple photodiodes. The optical sensor generally also includes a processing device or circuit for processing signals received from the light receiving sensor. The light emitting device and the light receiving sensor can be formed on a substrate, and a module cap can be assembled to the substrate over the light emitting device and the light receiving sensor to form an optical sensor module, also referred to as an optical sensor package. The light emitting device can include multiple light sources, such as multiple VCSELs.

[0056] The term "substrate assembly" corresponds to a subassembly of an optical sensor module. The substrate assembly generally includes a substrate and components mounted on the substrate, such as a light emitting device and a light receiving sensor. A module cap of the optical sensor module is generally assembled to the substrate over the components mounted on the substrate.

[0057] The optical sensor module may be affected by electromagnetic interference (EMI) from another electronic device.

[0058] 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 host device may be a camera, a phone (e.g., a smart phone), a smart watch, a tablet, a vehicle, or another device for which detecting the presence of and / or the distance to nearby objects may be useful.

[0059] Electromagnetic interference between the optical sensor module and the host device can include:

[0060] - electromagnetic waves emitted by components of the optical sensor module that may affect components of the host device; and / or

[0061] - Electromagnetic waves emitted by the host device that may affect the performance of the optical sensor module.

[0062] For example, potential sources of electromagnetic waves emitted by the optical sensor module may come from a light emitting device, for example from a light source of the light emitting device such as a VCSEL, from a driver such as a laser driver, from an inductor or even from conductive lines (wire bonds).

[0063] Furthermore, environments such as those with huge electromagnetic waves (e.g., data centers) may also interfere with the components of the optical sensor module and affect its performance.

[0064] In some applications, controlling the effects of EMI is important, such as protecting electronic components and circuits from EMI.

[0065] One solution to address the electromagnetic interference problem is to add a single metal shield over electromagnetically sensitive components.

[0066] However, a single metal shield may have several disadvantages. A single metal shield may require a large opening for the optical path. Depending on the method used, the manufacture of the metal shield may introduce a large number of steps, such as assembly steps, which leads to high costs and may modify or affect the operation of some components of the optical sensor module. Manufacturing may also introduce slots or gaps in the metal shield, such as for assembly or cleaning of surface mount technology (SMT) components, which may allow electromagnetic waves to pass through, which may be a source of EMI leakage. The optical path may also be affected by the single metal shield, resulting in an increase or uncontrolled level of alien crosstalk in the optical sensor module.

[0067] The inventors have proposed an optical sensor module that makes it possible to overcome all or part of the above-mentioned disadvantages, in particular to solve the electromagnetic interference problem, using an efficient and simple EMI protection capable of reducing EMI leakage and / or increasing EMI shielding, which can avoid changing the operation of some components of the optical sensor module and preferably avoid increasing the footprint of the optical sensor module and complicating the manufacturing method.

[0068] It may also be desirable for the optical sensor module to be able to manage electromagnetic interference through EMI protected openings.

[0069] Embodiments of a substrate assembly for an optical sensor module will be described below. These embodiments are non-limiting, and those skilled in the art will appreciate various variations based on the guidance of this description.

[0070] Figure 1A is a three-dimensional view of a substrate assembly 100 of an optical sensor module according to an embodiment. Figure 1B yes Figure 1A 1 is a cross-sectional view of a substrate assembly 100 . Figure 1B The cross-sectional view shows the Figure 1A The substrate assembly 100 is cut along the AA direction shown in FIG.

[0071] The substrate assembly 100 includes a plurality of components mounted on a top surface 101A of a substrate 101 .

[0072] The substrate assembly 100 includes a light emitting device 110, for example, including an LED (such as an infrared LED) and / or a laser (such as a VCSEL or an edge emitting laser (EEL)), and a light receiving sensor 120, for example, including a photodiode or multiple photodiodes (such as (one or more) SPADs), which are mounted on the top surface 101A of the substrate 101. The light emitting device 110 may include multiple light sources.

[0073] The substrate 101 may be a printed circuit board (PCB).

[0074] The light emitting device 110 is configured to emit a light signal at a specific frequency or frequency range, and the light receiving sensor 120 is adapted to detect a returned emitted light signal, such as a light signal reflected by an object. In one embodiment, the light emitting device 110 is configured to emit an infrared (IR) light signal, and the light receiving sensor 120 is adapted to detect a returned IR light signal, such as an IR light signal reflected by an object.

[0075] For example, the light emitting device 110 may include a first light source 111 and a second light source 112, each of which is mounted on the top surface 101A of the substrate 101, as described below. Figure 2D As seen in. Figure 1A and Figure 1B Only the second light source 112 is shown in FIG. The first light source 111 and the second light source 112 are, for example, a first VCSEL and a second VCSEL. The light emitting device 110 may further include a photodiode 113 mounted on the top surface 101A of the substrate 101. The photodiode 113 may be dedicated to monitoring the light source.

[0076] In a variant, the light emitting device may comprise only one light source. In another variant, the light emitting device may comprise more than two light sources.

[0077] In a variant, the light emitting device may not include a photodiode, and / or include another component that monitors the light source(s). In another variant, the light emitting device may include more than one photodiode.

[0078] The light emitting device 110 may be electrically coupled to the light receiving sensor 120 , such as through the substrate 101 .

[0079] The substrate assembly 100 may include a driver 103, such as a laser driver, configured to control the light emitting device 110, and a processing circuit 104 for processing an optical signal emitted by the light emitting device 110 and received by the light receiving sensor 120. The driver 103 and the processing circuit 104 may be mounted on the top surface 101A of the substrate 101. The driver 103 is mounted on the substrate 101 using, for example, a ball grid array technology.

[0080] The substrate assembly 100 may include other electrical circuits or components, such as an inductor 105 or other surface mount technology (SMT) components 106 also mounted on the top surface 101A of the substrate 101. Other SMT components 106 may include resistors. Additional SMT components may include capacitors.

[0081] A light emitting device 110 including light sources 111 , 112 and a photodiode 113 , a driver 103 , an inductor 105 , and some other SMT components 106 is mounted on a first region 101R of a substrate 101 .

[0082] The substrate assembly 100 further includes a first metal shield 130 mounted on the first region 101R of the substrate 101. The first metal shield 130 is preferably shaped and sized to surround and at least partially cover the components (at least the light emitting device 110, the driver 103, and the inductor 105) mounted on the first region 101R. Thus, the first metal shield 130 advantageously surrounds potential sources of electromagnetic waves emitted by the components of the substrate assembly.

[0083] The first metal shield 130 has a side wall 130B joined to the top wall 130A.

[0084] The first metal shield 130 may be referred to as a metal shield assembly, or included in a metal shield assembly.

[0085] The first metal shield 130 is electrically coupled to the substrate 101 , preferably coupled to a ground trace or a ground rail of the substrate 101 , to further improve the effectiveness of EMI protection, for example, for effective absorption of electromagnetic waves.

[0086] The first metal shield 130 includes a first opening 131 formed in the top wall 130A, which provides an optical path for light emitted by the light emitting device 110 and optionally transmitted to the light emitting device 110, that is, allows light emitted by the light emitting device and optionally transmitted to the light emitting device to pass through.

[0087] The shape and size of the first opening 131 are also designed so that the light emitting device 110 (i.e., the light source(s)) and optionally the photodiode can be vertically inserted into the first metal shield 130 through this first opening for mounting on the substrate 101. The size of the first opening 131 may include sufficient clearance for mounting these components on the substrate 101 through this first opening depending on the surface mounting method used.

[0088] For example, as shown, in a first plane parallel to the plane of the substrate 101, the area of ​​the first opening 131 can be at least equal to, for example, adjusted to, the area of ​​the (one or more) light sources and optionally the photodiode in the first plane. This allows the area of ​​the first opening to be limited to the area strictly necessary for installation to avoid increasing EMI leakage.

[0089] The area of ​​the first opening 131 may be a trade-off between EMI protection and mounting the light source(s) and optionally the photodiode onto the substrate 101 through this first opening.

[0090] The first opening 131 is configured for mounting (one or more) light sources and optionally photodiodes on the substrate 101 after assembling the first metal shield 130 on the substrate 101, for example to avoid affecting or modifying the light emitting device 110 during assembly of the first metal shield 130 on the substrate 101. For example, this can avoid contamination of the light emitting device 110 during assembly steps such as a reflow step.

[0091] In a variant, instead of a single first opening, there can also be a plurality of first openings, which do not necessarily have to engage with one another.

[0092] The metal of the first metal shield 130 is preferably selected to reflect and / or absorb electromagnetic waves generated by components mounted on the first region 101R to prevent the electromagnetic waves from leaving the substrate assembly 100, and to prevent the electromagnetic waves from leaving the optical sensor module, and, for example, to prevent affecting the host device. The metal of the first metal shield 130 may also be selected to reflect and / or absorb electromagnetic waves generated by another electronic device (such as a host device) or electromagnetic waves from the environment to prevent electromagnetic waves from affecting the performance of the components of the optical sensor module mounted on the first region. The metal of the first metal shield is, for example, copper or a copper alloy, stainless steel, or any conductive material that also has a relative magnetic permeability higher than 1.

[0093] The first metal shield 130 also includes an absorbent layer 132, or EMI absorbent layer, located on the inner surface of the top wall 130A of the first metal shield. The absorbent layer 132 faces the light emitting device 110. The absorbent layer includes a material suitable for absorbing electromagnetic waves, such as CHO-MUTE® manufactured by Parker Chomerics. TM The EMI absorber material commercialized under the name of EMI absorber, EMI absorber commercialized under the name of IDSOB, IDCIM by DoosungCorp, or EMI absorber commercialized by Laird. The absorber layer 132 has an opening facing the first opening 131 and its area is preferably equal to or larger than that of the first opening.

[0094] Although Figure 1A and Figure 1B Although not shown in the figure, the optical sensor module generally includes a module cap assembled to the substrate assembly 100 and adapted to at least partially enclose or cover the components (at least the light emitting device and the light receiving sensor) mounted on the substrate. The module cap also covers the metal shield assembly. "At least partially" means that not all components may be covered. For example, the module cap generally includes a first cap opening located above the light emitting device and a second cap opening located above the light receiving sensor. The first cap opening preferably faces the first opening of the first metal shield and has an area that is preferably equal to or greater than the area of ​​this first opening. The module cap may be substantially opaque to light at the wavelength used. The module cap may be mounted on Figure 1A The module cap may include a partition wall between the light emitting device and the light receiving sensor to form an optical isolator for substantially preventing a light beam from propagating internally between the light emitting device and the light receiving sensor.

[0095] Figure 2A , Figure 2B , Figure 2C and Figure 2D This is an example of manufacturing Figure 1A and Figure 1BTop view and three-dimensional views of an example of a method of substrate assembly 100 .

[0096] Figure 2A is a top view of a starting structure including substrate 101. Inductors 105 and other SMT components 106 are mounted on a first region 101R of substrate 101. Drivers 103 may also have been mounted on first region 101R using surface mount assembly technology such as ball grid array technology.

[0097] The first region 101R includes a first conductive pad 102A adapted to receive and connect the light sources 111 , 112 and the photodiode 113 , and a second conductive pad 102B corresponding to or connected to a ground trace of the substrate 101 .

[0098] Figure 2B is a top view of a structure obtained by assembling the first metal shield 130 including the absorbent layer 132 on the substrate 101 .

[0099] The first metal shield 130 may be assembled to the substrate 101 using surface mounting techniques, such as by forming a solder paste dot on the second conductive pad 102B and contacting the first metal shield 130 with the solder dot, and then reflowing the solder paste to form a solder joint 133. Other soldering techniques may be used. Alternatively, a conductive adhesive or other electrical coupling means between the first metal shield and the ground trace of the substrate may be used for assembly.

[0100] At the end of this assembly step, the first metal shield 130 is attached to the substrate 101 and is in electrical contact with the second conductive pad 102B and, thereby, the ground trace.

[0101] Figure 2C 1 is a three-dimensional view of the structure during the insertion of the first and second light sources 111 and 112 and the photodiode 113 into the first metal shield 130 through the first opening 131 .

[0102] Then, the first and second light sources 111 and 112 and the photodiode 113 are mounted on the substrate 101 , for example, using a die attach process.

[0103] Figure 2D 1 is a top view of the structure obtained after each of the first light source 111 and the second light source 112 and possibly the photodiode 113 are electrically connected to the substrate 101 through the first opening 131, for example using a wire bonding technique. Figure 2D As shown in FIG. 1 , a conductive wire 114 connects each light source to a third conductive pad 102C of the substrate 101 , but other techniques may be used to connect the light sources to the substrate.

[0104] In certain embodiments, such as Figure 2D As shown in FIG. 1 , in plan view, the first conductive pads 102A on which the light source(s) and optionally the photodiode are to be positioned are completely visible through the first openings 131. In other words, the projection of the first openings 131 vertically onto the substrate 101 completely encompasses the footprint of the first conductive pads 102A on the substrate 101. This means that, advantageously, the light source(s) and optionally the photodiode can be directly lowered vertically through the first openings 131 and into their final position on the substrate 101 and can be wire-bonded to these first conductive pads.

[0105] The light receiving sensor 120 and other components, such as the processing circuit 104 , may then be mounted on the substrate 101 .

[0106] Thus, components of the substrate assembly 100 that may serve as electromagnetic sources, such as the light emitting device 110, the driver 103, the inductor 105, or even the conductive line 114, are at least partially surrounded or contained within the first metal shield 130. The first metal shield 130 may allow for absorption and reflection of electromagnetic waves emitted by these components. The first metal shield 130 may also allow for protection of these components from electromagnetic waves provided from outside the first metal shield or even from outside the optical sensor module. In addition, the absorbent layer 132 of the first metal shield 130 allows for better absorption of electromagnetic waves emitted by electromagnetic sources, such as electromagnetic waves emitted by the light emitting device 110, the driver 103, the inductor 105, and / or the conductive line 114, thereby reducing EMI power intensity within this first metal shield, thereby reducing EMI leakage. Thus, the first metal shield 130 including the absorbent layer 132 allows for reduced EMI leakage (e.g., from leakage through the first opening 131), thereby providing efficient EMI protection.

[0107] Figure 3A is a three-dimensional view of a substrate assembly 300 of an optical sensor module according to another embodiment. Figure 3B It is shown Figure 3A A cross-sectional three-dimensional view of a detail of the substrate assembly 300 . Figure 3B The cross-sectional 3D view shows the Figure 3A Detail of the substrate assembly 300 cut into slightly less than half its width in the BB direction is shown in FIG. 1 and makes it easier to see the different components of the substrate assembly located below the first metal shield.

[0108] Figure 3A and Figure 3B The substrate assembly 300 and Figure 1A and Figure 1BThe main difference of the substrate assembly of FIG. 1 is that the first opening 131 of the first metal shield 130 is covered by a glass 350 including an electrically conductive trace 351. The conductive trace 351 in the glass 350 allows for managing EMI in the first opening 131, for example by providing EMI reflection in the first opening, thereby limiting EMI leakage and providing efficient EMI protection, even if the first opening is large.

[0109] The first metal shield 130 may be referred to as a metal shield assembly, or be included in a metal shield assembly.

[0110] The conductive trace material may be one or more of the following materials: copper (Cu), aluminum (Al), indium tin oxide (ITO), tungsten (W), titanium (Ti), gold (Au).

[0111] Figure 3A and Figure 3B The conductive traces 351 shown in FIG. 1 form a grid or a grid having a plurality of first linear portions 351A substantially parallel in a first direction in the glass plane and a plurality of second linear portions 351B substantially parallel in a second direction in the glass plane. The first direction and the second direction are, for example, substantially perpendicular to each other. Two adjacent first linear portions are separated by a first distance or a first pitch in the first direction, and two adjacent second linear portions are separated by a second distance or a second pitch in the second direction. Each of the first distance and the second distance is, for example, less than or equal to a fraction of the wavelength λ as defined above.

[0112] Each linear portion of the conductive trace 351 may be a thin portion, for example, having a thickness of less than 100 nanometers. The first pitch between the first linear portions 351A and the second pitch between the second linear portions 351B may be determined according to the frequency of the EMI to be managed, respectively. For example, the higher the frequency, the smaller the pitch may be.

[0113] Each pitch is, for example, smaller than the wavelength λ of the electromagnetic signal to be attenuated, and is, for example, a fraction of the wavelength λ, where λ is equal to:

[0114] λ=v / f

[0115] where v is the speed of light, and f is the frequency of the electromagnetic wave chosen to be attenuated.

[0116] The thickness and pitch of the conductive traces 351 may be a trade-off between the EMI protection function and the light transmittance of the glass 350. For example, when the conductive traces are less likely to affect the desired quality of light transmission, the conductive traces may be thicker and / or the pitch may be lower, alternatively, when the conductive traces may affect the desired quality of light transmission, the conductive traces may be thinner and / or the pitch may be higher.

[0117] A grid is an example of a pattern that can be used to form a conductive trace. A person skilled in the art can envision different patterns of conductive traces. For example, the conductive traces can include portions that are not perpendicular to each other, such as a zigzag pattern, thereby allowing the distance between patterns to be minimized.

[0118] Advantageously, the conductive trace 351 is grounded to provide additional EMI protection. For example, the conductive trace 351 is electrically coupled to the first metal shield 130 , such as in contact with the first metal shield 130 , and coupled to a ground trace of the substrate 101 through the first metal shield 130 .

[0119] Examples of conductive traces are described in more detail in French patent application No. 2311561 filed on October 25, 2023 in the name of STMICROELECTRONICS INTERNATIONAL NV (law firm reference number B22689), which is incorporated herein by reference to the maximum extent permitted by law.

[0120] Figure 3A and Figure 3B Other features of the substrate assembly 300 may be related to Figure 1A and Figure 1B The features of the substrate assembly 100 are similar to those of Figure 1A and Figure 1B The variations described in relation to the substrate assembly 100 may also be applicable to Figure 3A and Figure 3B The substrate assembly 300. Figure 1A and Figure 1B The optical sensor module is similarly Figure 3A and Figure 3B The optical sensor module generally includes a module cap assembled to a substrate assembly 300 .

[0121] Figure 3B An EMI absorbent layer 132 is shown located on the inner surface of the top wall 130A of the first metal shield 130. In a variation, Figure 3A and Figure 3B The substrate assembly 300 may not include an EMI absorber layer.

[0122] Figure 3A and Figure 3B The first opening 131 shown in FIG. Figure 1A and Figure 1B The first openings are substantially the same area, but this is not restrictive.

[0123] Figure 4 is an example for manufacturing Figure 3A and Figure 3B The substrate assembly 300 of FIG. 2A to FIG. 2D3D views of variants of the method.

[0124] from Figure 2D Starting with the structure of the first metal shield 130, the glass 350 with the conductive trace 351 is positioned on the top wall 130A of the first metal shield 130 so as to cover the first opening 131 and allow the conductive trace 351 to contact the first metal shield 130. Then, the conductive trace 351 is assembled to the top wall 130A, for example, using a conductive adhesive such as a conductive epoxy. Preferably, this assembly ensures electrical connection between the conductive trace 351 and the first metal shield 130.

[0125] The light receiving sensor 120 and other components, such as the processing circuit 104 , may then be mounted on the substrate 101 .

[0126] Figure 5A is a three-dimensional view of a substrate assembly 500 of an optical sensor module according to another embodiment. Figure 5B It is shown Figure 5A A cross-sectional three-dimensional view of a detail of substrate assembly 500 . Figure 5C yes Figure 5A 3D view of a variant of the baseplate assembly. Figure 5B The cross-sectional 3D view shows the Figure 5A Detail of substrate assembly 500 cut to approximately one third of its width in the CC direction is shown in FIG. 5 and makes it easier to see the different components of the substrate assembly located below the first and second metal shields.

[0127] FIG. 5A to FIG. 5C The substrate assembly 500 and Figure 1A and Figure 1B The main difference of the substrate assembly 500 is that the first opening 531 of the first metal shield 530 does not have to be adjusted to the size of the (one or more) light sources and optionally the photodiodes, including the mounting clearance, in order to mount the (one or more) light sources and optionally the photodiodes on the substrate 101. In other words, there is no need to find a trade-off between EMI protection and mounting through the first opening 531, and the first opening 531 can have a large area. In addition, the substrate assembly 500 also includes a second metal shield 534, which is suitable for being assembled to the first metal shield 530 above the first opening 531 once the light emitting device 110 is mounted and electrically connected to the substrate 101. The shape and size of the second metal shield 534 are preferably suitable for covering the first opening 531. For example, the second metal shield 534 is suitable for sealing the first opening 531.

[0128] The first metal shield 530 and the second metal shield 534 form a metal shield assembly.

[0129] The metal of the second metal shield 534 is preferably selected to be reflective and / or absorptive:

[0130] - electromagnetic waves generated by components mounted on the first region 101R to prevent the electromagnetic waves from leaving the substrate assembly 100 and also prevent the electromagnetic waves from leaving the optical sensor module and, for example, from affecting a host device;

[0131] - Electromagnetic waves generated by another electronic device (such as a host device) or electromagnetic waves from the environment to prevent the electromagnetic waves from affecting the performance of the components of the optical sensor module mounted on the first area.

[0132] The metal of the second metal shield may be the same as the metal of the first metal shield.

[0133] The metal shield assembly advantageously surrounds potential sources of electromagnetic waves emitted by components of the substrate assembly 500 mounted on the first region 101R of the substrate 101, such as the light emitting device 110, the driver 103 (described below), and the like. Fig. 6A (see ).

[0134] For example, Figure 5B As shown in , the second metal shield 534 is larger than the first opening 531 and is positioned to overhang on either side of the first opening, and the solder or conductive adhesive 536 positioned on the top wall 530A of the first metal shield 530 and on the edge of the second metal shield 534 seals the metal shield assembly. The use of solder or conductive adhesive allows the second metal shield to be electrically connected to the first metal shield, such as coupling the second metal shield to ground through the first metal shield. This assembly technique is a non-limiting example, and other assembly techniques can be envisioned by those skilled in the art. For example, the second metal shield can be assembled below the first opening and / or the shape and size of the second metal shield can be adjusted to the first opening.

[0135] The first metal shield and the second metal shield may be coupled or joined to each other by welding, such as laser welding.

[0136] The second metal shield 534 includes at least a second opening that provides an optical path for light emitted by the light emitting device 110 and optionally transmitted to the light emitting device 110 . FIG. 5A to FIG. 5C The second metal shield 534 shown in FIG. 1 includes a plurality of second openings: two second openings 535A, 535B provide optical paths 501, 502 for the light emitted by the first light source 111 and the second light source 112, respectively, and another second opening 535C allows the light transmitted to the photodiode 113 to pass through. The size of each second opening is designed (e.g., adjusted) for the optical path to be provided.

[0137] like Figure 5B As shown in FIG, in some embodiments, when viewed vertically through the second opening, the first conductive pads 102A on which the light source(s) and optionally the photodiode are to be positioned are at least partially hidden by the second metal shield 534. In other words, the projection of the second opening vertically onto the substrate 101 does not completely encompass the footprint of these first conductive pads on the substrate 101.

[0138] FIG. 5A to FIG. 5C The metal shield assembly allows the light emitting device 110 (e.g., (one or more) light sources and optionally photodiodes) to be more easily mounted and electrically connected to the substrate 101 before the second metal shield 534 is assembled to the first metal shield 530, while limiting the area of ​​the opening in the metal shield assembly once the second metal shield 534 is assembled, and the second opening is preferably mainly dedicated to (one or more) light paths, thereby limiting EMI leakage and providing efficient EMI protection. In addition, the first opening 531 can be larger than the first opening 531. Figure 1A and Figure 1B The first opening 131 is easier to machine.

[0139] The second metal shield 534 may be substantially flat, such as Figure 5C as shown in , or may be recessed, as in Figure 5A and Figure 5B as shown in . Figure 5A and Figure 5B The recessed form allows limiting the size of the second openings 535A, 535B, 535C as it allows positioning these second openings closer to the light sources 111, 112 and / or the light receiving photodiode 113 of the light emitting device 110, thereby providing better EMI shielding.

[0140] FIG. 5A to FIG. 5C The first metal shield 530 does not include an EMI absorber layer. In a variation, FIG. 5A to FIG. 5C The first metal shield 530 and / or the second metal shield 534 may include an EMI absorber layer.

[0141] FIG. 5A to FIG. 5C Other features of the substrate assembly 500 may be related to Figure 1A and Figure 1B The features of the substrate assembly 100 are similar to those of Figure 1A and Figure 1B The variations described in relation to the substrate assembly 100 may also be applicable to FIG. 5A to FIG. 5C The substrate assembly 500. Figure 1A and Figure 1B The optical sensor module is similarly FIG. 5A to FIG. 5C The optical sensor module generally includes a module cap assembled to a substrate assembly 500 .

[0142] FIG. 5A to FIG. 5C Embodiments may advantageously be used with Figure 3A and Figure 3B The conductive trace is preferably electrically coupled to the second metal shield, for example in contact with the second metal shield, and can be coupled to ground through the second metal shield.

[0143] Fig. 6A and Figure 6B is an example for manufacturing FIG. 5A to FIG. 5C The substrate assembly 500 of FIG. 2A to FIG. 2D Top view and 3D views of variations of the method.

[0144] Fig. 6A is a top view of the starting structure, which is similar to that of FIG. 5 except that the first metal shield 530 has a larger first opening 531 and this first opening has a simpler shape. Figure 2D The first light source 111 and the second light source 112 and the photodiode 113 of the light emitting device 110 have been mounted through this larger first opening 531 and are electrically connected to the substrate 101 .

[0145] Figure 6B 5 is a three-dimensional view of the structure obtained after assembling the second metal shield 534 to the first metal shield 530 to cover the first opening 531 using, for example, solder or a conductive adhesive 536 .

[0146] Figure 7 is a three-dimensional view of a substrate assembly 700 of an optical sensor module according to another embodiment.

[0147] Figure 7 The substrate assembly 700 and Figure 1A and Figure 1B The main difference of the substrate assembly is that the first opening 731 of the first metal shield 730 (described below) Fig. 8A ) does not have to be adjusted to the size of the (one or more) light sources and optionally the photodiodes in order to mount the (one or more) light sources and optionally the photodiodes on the substrate 101, including the mounting gap, similar to FIG. 5A to FIG. 5C In other words, there is no need to find a trade-off between EMI protection and installation for the first opening, and the first opening 731 can have a large area. In addition, the substrate assembly 700 also includes a second metal shield 734, which is suitable for being assembled to the first metal shield over the first opening 731 once the light emitting device 110 is installed and electrically connected to the substrate 101.

[0148] Figure 7 The substrate assembly 700 and FIG. 5A to FIG. 5C The main difference of the substrate assembly is that the second metal shield 734 not only covers the first opening 731, but also covers the top wall 730A of the first metal shield 730 (the top wall 730A is described below). Fig. 8A (see ).

[0149] The first metal shield 730 and the second metal shield 734 form a metal shield assembly. For example, the first metal shield 730 forms a metal frame, and the second metal shield 734 constitutes a metal cover.

[0150] The metal shielding assembly advantageously surrounds potential sources of electromagnetic waves emitted by components of the optical sensor module mounted on the first region 101R of the substrate 101, such as the light emitting device 110, the driver 103, the inductor 105 (described below), and the like. Fig. 8A (see ).

[0151] exist Figure 7 In the embodiment, the second metal shield 734 is substantially flat. This is not limiting, and those skilled in the art may envision other shapes. For example, in a variation, the second metal shield may be recessed, or may have a recessed portion, such as above the light emitting device, such as Figure 5A and Figure 5B A second metal shield 534 is provided.

[0152] For example, Figure 7 , the second metal shield 734 can be assembled to the side wall 730B of the first metal shield 730. In more detail, the second metal shield 734 has a top wall 734A, and the top wall 734A has an edge 734B, which is bent and extended substantially orthogonally relative to the top wall. These edges are conformal to seal the upper edges of at least some of the side walls 730B of the first metal shield 730. The second metal shield 734 also includes a fixing tab 736, which is adapted to cooperate with the slot 733 positioned in the top wall 730A of the first metal shield 730.

[0153] This assembly technique ensures electrical connection between the second metal shield 734 and the first metal shield 730 without using a conductive adhesive or solder for this purpose. Therefore, the second metal shield 734 can be coupled to the ground through the first metal shield 730. Figure 7 The assembly of the second metal shield 734 can be compared FIG. 5A to FIG. 5CThe assembly of the second metal shield 534 is easier. This assembly technique is a non-limiting example, and those skilled in the art may encompass other assembly techniques with or without the use of conductive adhesives or solder. For example, the second metal shield may include a clip adapted to be clipped to the side wall of the first metal shield, or may be inserted into the interior of the first metal shield and contact the side wall of the first metal shield, or the second metal shield may be assembled to the top wall of the first metal shield.

[0154] The top wall 734A of the second metal shield 734 includes at least a second opening that provides an optical path for light emitted by the light emitting device 110 and optionally transmitted to the light emitting device 110 . Figure 7 The second metal shield 734 shown in FIG. 1 includes a plurality of second openings: two second openings 735A, 735B provide optical paths for light emitted by the first light source 111 and the second light source 112, respectively, and another second opening 735C allows passage of light transmitted to the photodiode 113. The size of each second opening is designed (e.g., adjusted) for the optical path to be provided.

[0155] The top wall 734A of the second metal shield 734 may also include a third opening 737 adapted to access the securing tabs 736 for clamping thereof and / or for positioning the second metal shield 734 relative to the first metal shield 730 .

[0156] The top wall 730A of the first metal shield 730 may also include a fourth opening 732 located above the inductor 105, as described below. Fig. 8A for visual inspection.

[0157] exist Figure 7 In the embodiment, both the first metal shield 730 and the second metal shield 734 do not include an EMI absorbent layer. In a variant, Figure 7 The first metal shield 730 and / or the second metal shield 734 may include an EMI absorber layer on an inner top surface thereof.

[0158] Figure 7 The embodiments can be used with Figure 3A and Figure 3B The conductive trace is preferably electrically coupled to the second metal shield, for example in contact with the second metal shield, and can be coupled to ground through the second metal shield.

[0159] Figure 7 Other features of the substrate assembly 700 may be related to Figure 1A and Figure 1BThe features of the substrate assembly 100 are similar to those of Figure 1A and Figure 1B The variations described in relation to the substrate assembly 100 may also be applicable to Figure 7 The substrate assembly 700. Figure 1A and Figure 1B The optical sensor module is similarly Figure 7 The optical sensor module generally includes a module cap assembled to a substrate assembly 700 .

[0160] In some embodiments, when viewed vertically through the second opening, the first conductive pads 102A on which the light source(s) and optionally the photodiode are to be positioned are at least partially hidden by the second metal shield 734. In other words, the projection of the second opening vertically onto the substrate 101 does not completely encompass the footprint of these first conductive pads on the substrate 101.

[0161] Figure 7 The metal shield assembly allows for easier mounting and electrical connection of the light emitting device 110 (e.g., (one or more) light sources and optionally a photodiode) to the substrate 101, as well as inspection of surface mounted components before assembling the second metal shield 734 to the first metal shield 730, while limiting the area of ​​the opening in the metal shield assembly once the second metal shield 734 is assembled, with the second opening preferably being primarily dedicated to (one or more) optical paths, thereby limiting EMI leakage and providing efficient EMI protection.

[0162] Fig. 8A and Figure 8B is an example for manufacturing Figure 7 The substrate assembly 700 FIG. 2A to FIG. 2D Top view and 3D views of variations of the method.

[0163] Fig. 8A is a top view of the starting structure, except that the first metal shield 130 is Figure 7 The first metal shield 730 is replaced by the starting structure Figure 2D The first and second light sources 111 and 112 and the photodiode 113 of the light emitting device 110 have been mounted and electrically connected to the substrate 101 through the large first opening 731 . The inductor 105 and other SMT components 106 are mounted on the substrate 101 and contained within the first metal shield 730 .

[0164] Fig. 8A The fourth opening 732 of the first metal shield 730 above the inductor 105 is shown, as well as the slot 733 adapted to cooperate with the fixing tab 736 of the second metal shield 734. Fig. 8AAs shown in , the first opening 731 may extend over the driver 103 and may also extend over some of the other SMT components 106 , such as for visual inspection.

[0165] Figure 8B is a three-dimensional view of the structure obtained after the second metal shield 734 is assembled (e.g., clamped) to the first metal shield 730, such as by sealing the bent edge 734B of the second metal shield around the upper edge of the side wall 730B of the first metal shield and by inserting the fixing tab 736 into the groove 733.

[0166] Various embodiments and variations have been described. Those skilled in the art will appreciate that certain features of these embodiments may be combined, and those skilled in the art will readily conceive of other variations.

[0167] Finally, actual implementation of the embodiments and variations described herein is well within the capabilities of those skilled in the art based on the functional description provided above.

Claims

1. A substrate assembly for an optical sensor module, the substrate assembly comprising: a light emitting device mounted on the first region of the substrate; a metal shield assembly including a first metal shield assembled to the substrate over the first region; as well as The first metal shielding member includes a first opening, the first opening provides an optical path for light emitted by the light emitting device, and the first opening is designed with a size such that the light emitting device can be inserted into the first metal shielding member through the first opening.

2. The substrate assembly of claim 1, wherein the first metal shield is sized to surround and at least partially cover the light emitting device, the first metal shield comprising side walls joined by a top wall, the top wall comprising the first opening.

3. The substrate assembly of claim 1, wherein the light emitting device comprises: at least one light source, the first opening providing a light path for light emitted by the at least one light source and being sized so that the at least one light source can be inserted into the interior of the first metal shield through the first opening and mounted to the substrate; as well as The photodiode is configured to monitor the light emitting device, the first opening also provides an optical path for light transmitted to the photodiode, and is further designed with dimensions such that the photodiode can be inserted into the first metal shield through the first opening and mounted on the substrate. 4 . The substrate assembly of claim 1 , further comprising a driver mounted on the first region of the substrate, the driver configured to control the light emitting device. The base plate assembly of claim 4 , wherein the first opening extends above the driver.

6. The substrate assembly of claim 1, wherein the first metal shield is electrically coupled to the substrate, including a ground trace electrically coupled to the substrate.

7. The substrate assembly of claim 1, wherein the metal shield assembly further comprises a second metal shield assembled to the first metal shield and at least partially covering the first opening, the second metal shield comprising at least a second opening, the second opening allowing light emitted by or transmitted to the light emitting device to pass therethrough, the second metal shield being electrically coupled to or in contact with the first metal shield.

8. The substrate assembly of claim 7, wherein the second metal shield includes a recessed portion extending into the interior of the metal shield assembly.

9. The substrate assembly of claim 7, wherein the second metal shield seals the first opening.

10. The substrate assembly of claim 7, wherein the second metal shield at least partially closes the first metal shield.

11. The substrate assembly of claim 1, wherein the metal shield assembly includes an absorbent layer positioned on an inner surface of the metal shield assembly facing the light emitting device, including being positioned on an inner surface of the first metal shield facing the light emitting device.

12. The substrate assembly of claim 1 further comprising glass assembled to the first metal shield over the first opening, the glass comprising electrically conductive traces electrically coupled to or in contact with the first metal shield, including ground traces coupled to the substrate through the first metal shield.

13. The substrate assembly of claim 1, wherein the metal of the metal shield assembly is selected to reflect or absorb electromagnetic waves, wherein the metal is copper, copper alloy, stainless steel or any conductive material that also has a relative magnetic permeability higher than 1.

14. An optical sensor module, comprising: The substrate assembly according to claim 1; as well as A module cap is assembled to the substrate and is adapted to at least partially cover the metal shield assembly and components mounted on the substrate.

15. A method of manufacturing a substrate assembly for an optical sensor module, the method comprising: assembling a first metal shield to the substrate over a first region of the substrate, the first metal shield comprising a first opening providing an optical path for light emitted by a light emitting device to be mounted on the first region; as well as The light emitting device is mounted to the first area through the first opening.

16. The method of claim 15, further comprising, after mounting the light emitting device to the first area through the first opening, assembling glass including electrically conductive traces to the first metal shield over the first opening, the conductive traces electrically coupled to or in contact with the first metal shield.

17. The method of claim 15, further comprising: After the light emitting device is mounted to the first area through the first opening, a second metal shield is assembled to the first metal shield so as to at least partially cover the first opening, the second metal shield includes at least a second opening, the second opening allows light emitted by or transmitted to the light emitting device to pass through, and the second metal shield is electrically coupled to the first metal shield or in contact with the first metal shield.

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