Optical sensor module

Abstract

The invention relates to an optical sensor module. An optical sensor module is provided. An exemplary optical sensor module includes: a substrate including a first conductive pad; a module cap assembled on the substrate; a connection flexure incorporated in the module cap, the connection flexure adapted to electrically couple at least one of the first conductive pads to at least one component mounted on and / or within the module cap; the connection flexure includes at least one metal layer that is covered by or encapsulated in at least one dielectric layer.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the priority of French patent application No. 2311581, entitled “Modulede Capteur Optique”, filed on October 25, 2023, which is hereby incorporated 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 do this without physically contacting the object. Certain 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 a variety of electronic devices, such as cameras, mobile phones (including smartphones), smart watches, tablets, vehicles, machinery and other devices to detect the presence of and / or the distance to nearby objects. Upon 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, sending an alarm signal, coupling or decoupling electrical communications, or any other desired function.

[0005] An optical sensor typically includes components such as a light emitting device, a light receiving sensor (or image sensor), and a processing device typically 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 typically formed with a first opening located over the light emitting device and a second opening located over the light receiving sensor.

[0006] Generally speaking, the light emitting device emits a light signal or light beam through the first opening. If an object is outside the optical sensor module and close enough, the light signal can be emitted by the object through the second opening toward the light receiving sensor. The light receiving sensor can then generate an electrical signal indicative of the received light signal, which can be transmitted to the processing device to process the received light signal, for example to determine the presence of an approaching object and / or the distance to it.

[0007] The light emitting device for generating the light beam is usually covered by glass to protect the device from dust, the glass being relatively transparent to the wavelength of light used. The first opening above the light emitting device may be covered by glass.

[0008] Improvements in optical sensor modules are needed, particularly to improve electrical coupling between a substrate and components mounted in and / or on a cap, such as electrical coupling between a substrate and conductive elements (eg, conductive traces) in glass. Summary of the invention

[0009] An embodiment addresses all or some of the disadvantages of known optical sensor modules.

[0010] An embodiment provides an optical sensor module, including:

[0011] - a substrate comprising a first conductive pad;

[0012] -Module cap, assembled on the base plate;

[0013] - a connection flexure incorporated in the module cap, the connection flexure being adapted to electrically couple at least one of the first conductive pads to at least one component mounted on and / or in the module cap;

[0014] The connection flexure comprises at least one metal layer covered by or encapsulated in at least one dielectric layer.

[0015] In one embodiment:

[0016] - the connection flexure is over-moulded in the module cap; and / or

[0017] - The module cap is an electrically conductive molded cap, for example formed from a molding material comprising electrically conductive particles dispersed therein.

[0018] In one embodiment:

[0019] - said at least one metal layer of said connection flexure comprises, for example terminates in, a plurality of second conductive pads, said second conductive pads being suitable for coupling with a plurality of first conductive pads of the substrate; and

[0020] - said at least one dielectric layer of the connection flexure comprises, for example terminates in, a plurality of insulating elements, each second conductive pad being interposed between two insulating elements.

[0021] In one embodiment, the optical sensor module further comprises a light emitting device, the module cap at least partially covers the light emitting device and comprises a first opening above the light emitting device, the light emitting device being, for example, one of the at least one component.

[0022] In one embodiment, the optical sensor module further comprises glass, wherein the glass is located in the first opening or between the first opening and the light emitting device, and / or covers the first opening, and is suitable for transmitting an optical signal emitted by the light emitting device, wherein the glass comprises a conductive trace corresponding to a first component of the at least one component, and the connecting flexible member is electrically coupled to the conductive trace, for example, by a conductive wire formed by conductive wire bonding.

[0023] In one embodiment, the second component of the at least one component is located on the connecting flexible member. For example, the second component includes at least a part of the light emitting device.

[0024] In one embodiment, the connecting flexible member comprises at least a recess adapted to receive the second component.

[0025] In one embodiment, the connecting flexible member comprises:

[0026] at least one end portion configured to be connected to the substrate, the second conductive pad and the insulating element being defined in the at least one end portion, and

[0027] - an upper portion, the upper portion being at least partially in contact with the inner surface of the module cap, the recess being defined in the upper portion.

[0028] In one embodiment, the connecting flexible member comprises two end portions and two interconnecting portions, wherein each end portion is connected to the upper portion via one of the interconnecting portions, and each interconnecting portion is arranged substantially perpendicular to the upper portion.

[0029] In one embodiment, the connecting flexible member comprises:

[0030] - a first metal layer electrically coupled to the second element, for example via a conductive line, the first metal layer being covered by a first dielectric layer of the at least one dielectric layer;

[0031] - a second metal layer configured to be connected to ground, the second metal layer being covered by a second dielectric layer of the at least one dielectric layer;

[0032] a third metal layer located in the recess and electrically isolated from the first metal layer, the second component being connected to the third metal layer, for example located on the third metal layer;

[0033] - a dielectric core interposed between the first metal layer and the second metal layer; and

[0034] - at least one connecting via defined in the dielectric core and electrically coupling the third metal layer to the second metal layer. Preferably, the first metal layer, the second metal layer and / or the third metal layer are some of the at least one metal layer of the connecting flexure.

[0035] In one embodiment, the recess passes through the entire thickness of the first dielectric layer and the first metal layer up to the dielectric core.

[0036] In one embodiment, the connection flexure includes a plurality of bonding pads defined on an upper portion of the connection flexure, each bonding pad being configured to be electrically coupled to the second component, for example, via a conductive line.

[0037] In one embodiment, the bonding pad passes through the entire thickness of the first dielectric layer up to the first metal layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above-mentioned features and advantages and other features and advantages will be explained in detail in the following description of specific embodiments given by way of illustration and not by way of limitation with reference to the accompanying drawings, in which:

[0039] Figure 1 is a three-dimensional view of an example of an optical sensor module;

[0040] Figure 2A , Figure 2B and Figure 2C is a three-dimensional view of an optical sensor module according to an embodiment;

[0041] Figure 3A yes Figure 2B and 2C A schematic cross-sectional view of a connecting flexible member;

[0042] Figure 3B is a schematic cross-sectional view of a connection flexure of an optical sensor module according to another embodiment;

[0043] Figure 4A , Figure 4B , Figure 4C , Figure 4D , Figure 4E , Figure 4F , Figure 4G and Figure 4H It is shown in Figure 2A A top view and a three-dimensional view of a method of assembling a connecting flexure to a module cap in an optical sensor module;

[0044] Figure 5A is a cross-sectional three-dimensional view of an optical sensor module according to another embodiment;

[0045] Figure 5B yes Figure 5A A top view of an optical sensor module;

[0046] Figure 5C It is shown Figure 5A and 5BA top view of a detail of a connection flexure of an optical sensor module; and

[0047] Figure 5D It is shown Figure 5C A cutaway 3D view of a detail of a connected flexure. DETAILED DESCRIPTION

[0048] The same or similar features in the various drawings are designated by the same or similar reference numerals. In particular, common structural and / or functional features in various embodiments may have the same reference numerals, and may be provided with the same structure, dimensions, and material properties.

[0049] For the sake of clarity, only operations and elements that are useful for understanding the embodiments described herein are shown and described in detail. In particular, not all components of the optical sensor are described in detail, and the described embodiments are compatible with conventional optical sensors. For example, the light emitting device, the light receiving sensor, and other components of the optical sensor, such as the processing device, are not described in detail. Similarly, not all components of the optical sensor module are described in detail, and the described embodiments are compatible with conventional optical sensor modules.

[0050] Unless otherwise specified, when two elements are referred to as being connected together, this means a direct connection without any intermediate elements other than conductors, and when two elements are referred to as being coupled together, this means the two elements may be connected or they may be coupled via one or more other elements.

[0051] In the following disclosure, unless otherwise stated, when referring to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or referring to relative position qualifiers, such as the terms "upper", "lower", "high", "lower", etc., or referring to direction qualifiers, such as "horizontal", "vertical", etc., reference is made to the orientation shown in the accompanying drawings, or to the optical sensor module oriented during normal use.

[0052] Unless otherwise indicated, the expressions "about", "approximately", "substantially" and "approximately" mean within 10%, preferably within 5%.

[0053] In the following disclosure, unless otherwise stated, when reference is made to glass, it includes elements made of a material that is relatively transparent to the wavelengths of light used, for example having a transmittance of 90% or more to those wavelengths. This includes, but is not limited to, glass materials or plastic materials. Glass can be formed from a solid single material or by assembling multiple materials, in which case a portion of the glass can be in a transparent material. The glass may include (or consist of) a glass window, a lens or multiple lenses and / or an optical filter (more generally, an optical member).

[0054] In the following disclosure, unless otherwise specified, when a filter is mentioned, it is meant to be an optical filter.

[0055] In the following disclosure, unless otherwise stated, when referring to a conductive element, such as a conductive trace, pad, strip, or lead, it refers to an electrically conductive element.

[0056] In the following disclosure, when reference is made to a connecting flexure or "flex," it is meant a strip suitable for electrically coupling or connecting two elements, which strip has both flexibility, such as allowing it to bend according to a given curvature, and mechanical rigidity, such as maintaining that curvature once bent.

[0057] Embodiments are directed to various optical sensor modules.

[0058] 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 combined functions, such as a combination of at least two of the above modules, or other functions, such as a combination of a proximity detector module with a floodlight and / or a dot projector.

[0059] The optical sensor generally includes a light emitting device and a light receiving sensor. The optical sensor generally also includes a processing device for processing a signal received from the light receiving sensor. The light emitting device and the light receiving sensor may be formed on a substrate, and a cap may be attached to the substrate over the light emitting device and the light receiving sensor to form an optical sensor module (also referred to as a light sensor package). The cap is generally formed with a first opening located over the light emitting device and a second opening located over the light receiving sensor.

[0060] As explained in the background section above, the light emitting device is usually covered by glass for protecting the device, for example from dust, the glass being relatively transparent to the wavelength of light used. The glass may cover the first opening. The glass may also act as a diffuser, suitable for reducing the intensity of the emitted light beam to a certain extent, for example for safety reasons, such as protecting the user.

[0061] Figure 1 is a three-dimensional view of an example of an optical sensor module.

[0062] The optical sensor module 100 includes a light emitting device 110, for example, including a light emitting diode (LED) (such as an infrared LED) and / or a laser (such as a vertical cavity surface emitting laser (VCSEL)), and a light receiving sensor 120 (such as an image sensor), for example, including a photodiode or multiple photodiodes, such as one or more SPADs. The light emitting device 110 and the light receiving sensor 120 are mounted on a substrate 102.

[0063] The substrate 102 may be a printed circuit board (PCB).

[0064] The light emitting device 110 is configured to emit a light signal or light beam 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 a light signal reflected by an object.

[0065] Figure 1 The light emitting device 110 includes first and second light sources 111, 112 mounted on first and second inserts 141, 142, respectively, and the first and second inserts 141, 142 are mounted on the top surface 102A of the substrate 102. The first and second light sources 111, 112 are, for example, first and second VCSELs. In a variant, the light source can be mounted on the substrate without an insert.

[0066] In a variant, the light emitting device may comprise only one light source, such as a VCSEL, mounted on a substrate, for example via an interposer, or even without an interposer.

[0067] The light emitting device 110 may be electrically coupled to the light receiving sensor 120 , such as through the substrate 102 .

[0068] The upper surface 102A of the substrate 102 includes a conductive pad 106 (a first conductive pad), which is located, for example, at or near an edge of the substrate.

[0069] The optical sensor module 100 includes a laser driver 144 configured to control the first and second light sources 111, 112. The laser driver 144 may be located in the same cavity as the light emitting device 110, as described below. This is not limiting, and other configurations may be considered by those skilled in the art.

[0070] The optical sensor module 100 may include a processing circuit (not shown). Figure 1 ), which may be configured to process the light signal emitted by the light emitting device 110 and received by the light receiving sensor 120. The processing circuit may be mounted on the top surface 102A of the substrate 102.

[0071] The optical sensor module 100 includes other circuits or electronic components, such as surface mount technology (SMT) components 145, which are also mounted on the top surface 102A of the substrate 102. The SMT components 145 may include resistors. Other SMT components may include capacitors.

[0072] The light receiving sensor 120 can be coupled to the substrate 102 using a conductive connector (e.g., a conductive wire), and / or can be fixed to the substrate 102, such as by an adhesive material or solder. The adhesive material can be any material suitable for fixing the light receiving sensor 120 to the substrate, such as tape, paste, glue.

[0073] The module cap 130 having the first opening 131 and the second opening 132 is attached or bonded to the substrate 102 and is adapted to at least partially surround or cover the components mounted on the substrate 102, at least the light emitting device 110, the light receiving sensor 120, the inserts 141 and 142, the laser driver 144 and the SMT component 145. At least partially means that not all components may be covered, for example, the first opening and the second opening do not cover the components located below the openings. The module cap 130 may be substantially opaque to the wavelength of light used.

[0074] The first and second openings are located at the top surface 130A of the module cap 130. The first opening 131 is located above the light emitting device 110, and the second opening 132 is located above the light receiving sensor 120. In the example shown, the first opening 131 is rectangular and the second opening 132 is circular, but this is not restrictive and other forms are possible.

[0075] The module cap 130 may include a separation wall 133 between the light emitting device 110 and the light receiving sensor 120. The separation wall 133 may form an optical isolator for substantially preventing a light beam from propagating internally between the light emitting device 110 and the light receiving sensor 120 in the module cap 130. For example, the separation wall 133 defines a first cavity 136 and a second cavity 137, wherein the first cavity 136 includes a first opening 131 above the light emitting device 110 and the second cavity 137 includes a second opening 132 above the light receiving sensor 120. As described above, the laser driver 144 may be located in the first cavity 136 together with the light emitting device 110.

[0076] The module cap 130 may be a plastic cap and / or a molded cap formed of a molded material, such as a resin, a liquid crystal polymer (LCP), nylon or other engineering plastics. The module cap 130 may be formed using an injection method. In some examples, the module cap may be conductive.

[0077] The optical sensor module 100 further includes:

[0078] - glass 150, located in the first opening 131, or between the first opening 131 and the light emitting device 110, suitable for transmitting the optical signal emitted by the light emitting device; and

[0079] An optical filter 160 , located in the second opening 132 , or between the second opening 132 and the light receiving sensor 120 , adapted to transmit the optical signal reflected toward the light receiving sensor.

[0080] The glass 150 preferably covers the first opening 131. The glass 150 is preferably attached to the module cap 130. For example, the glass 150 sits on a mounting 139 formed in the first opening 131 and is mounted on the outside of the module cap 130. In a variation, the glass may be mounted inside the module cap.

[0081] Similarly, the optical filter 160 preferably covers the second opening 132. The optical filter 160 is preferably attached to the module cap 130. For example, the optical filter 160 is located inside the module cap 130. In one variation, the optical filter may be mounted outside the module cap.

[0082] The glass 150 may include two optical surfaces, which may be two beam shapers 151A and 151B, wherein the first beam shaper 151A is located above the first light source 111, and the second beam shaper 151B is located above the second light source 112. The glass 150 may be a lens or a lens pad.

[0083] The optical sensor module 100 may further include a second lens 162 located between the optical filter 160 and the light receiving sensor 120 .

[0084] Glass 150 may include a conductive trace 152, which may be embedded in the glass. Glass 150 may further include a conductive pad 154 (third conductive pad) coupled to conductive trace 152, such as two third conductive pads, each located at an end of the conductive trace.

[0085] In the following disclosure, a conductive trace may be referred to as a “trace.” A conductive pad may be referred to as a “pad” in the following disclosure.

[0086] The conductive traces may be one or more of the following materials: copper (Cu), aluminum (Al), tungsten (W), titanium (Ti), gold (Au), indium tin oxide (ITO), or other metals or metal alloys.

[0087] Conductive trace 152 can be a thin and / or fine trace, for example having a width of less than 1 micron and / or a thickness of less than 100 nanometers, but is not limited to these values. The width and thickness of the conductive trace can be a compromise between its function and the light transmittance of the glass. For example, in cases where the trace is less likely to limit light transmission, the conductive trace can be wider and / or thicker, while in cases where the trace is likely to limit light transmission, the conductive trace can be thinner and / or thinner.

[0088] Typically, the conductive traces 152 are arranged to be coupled to a conductive rail that is configured to be at a fixed voltage (eg, ground), which is typically connected to or included in the substrate 102 .

[0089] The conductive traces 152 can be used as protection against electromagnetic interference (EMI) passing through the first opening 131 of the module cap 130, for example by providing EMI reflection in the first opening. For example, when the optical sensor module 100 is included in an electronic device, electromagnetic interference may be generated between the optical sensor module and the electronic device. The electronic device can be a camera, a smartphone, a smart watch, a tablet, a vehicle, a machine, or other device that can be used to detect the presence of a nearby object and / or the distance to it. The pitch and pattern of the conductive traces can be determined according to the frequency of the EMI to be managed. For example, the higher the frequency, the lower the pitch can be.

[0090] Conductive traces 152 may also be used to manage safety issues associated with light emitting device 110, i.e., to detect if glass 150 is removed or otherwise becomes detached from module cap 130. If glass 150 is removed or detached, it may no longer function as a diffuser suitable for reducing the intensity of the emitted light beam and may no longer protect the user. When glass 150 is in place, conductive leads 134, conductive wires 155, and conductive traces 152, for example, through conductive paths in substrate 102, form a conductive loop. However, if glass 150 becomes detached, the circuit in the conductive loop may be opened, the detection circuit may detect the open circuit, and, for example, light emitting device 110 may be disabled.

[0091] In a variant (not shown), the filter 160 may also include a second conductive trace.

[0092] Examples of conductive traces are described in more detail in French patent application 2311561 (law office number B22689), entitled “Modulede Capteur Optique,” ​​filed on October 25, 2023, in the name of STMICROELECTRONICS INTERNATIONAL NV, which is incorporated herein by reference to the maximum extent permitted by law.

[0093] The optical sensor module 100 also includes two conductive leads 134 assembled to the module cap 130, such as being overmolded therein. The conductive leads 134 are configured and positioned to electrically couple the conductive traces 152 of the glass 150 to the substrate 102. The conductive leads 134 are typically rigid, such as a lead frame.

[0094] Each conductive lead 134 may be a single conductive sheet, such as a single metal sheet.

[0095] Each conductive lead 134 includes a first end 134A coupled (e.g., connected) to the substrate 102 through one of the first conductive pads 106, and a second end 134B coupled (e.g., connected) to the conductive trace 152 through one of the third conductive pads 154. The first end 134A of each conductive lead 134 may be coupled to one of the first conductive pads 106 by a conductive adhesive, such as a conductive tape, paste or glue, or a conductive solder. The second end 134B of each conductive lead 134 may be coupled to the third conductive pad 154 by a conductive wire 155 (which is formed by wire bonding and may be referred to as a "wire bond") or by a conductive adhesive or a conductive solder.

[0096] Examples of conductive lines are described in more detail in French patent application 2311572 (law office number B22688), entitled “Modulede Capteur Optique,” ​​filed on October 25, 2023 in the name of STMICROELECTRONICS INTERNATIONAL NV, which is incorporated herein by reference to the maximum extent permitted by law.

[0097] However, conductive leads, and particularly lead frames, have several disadvantages.

[0098] Lead frames are typically rigid and have a low tolerance for relative movement of the components to which they are connected and / or dimensional variations between those components and the lead frame, which can result in delamination.

[0099] Furthermore, it may be of interest to have a plurality of pads at the first end 134A of the conductive lead 134. However, due to the methods by which conductive leads (such as lead frames) are typically manufactured, it may be difficult to have a small pitch between pads, and therefore it may be difficult to have such a plurality of pads. In practice, lead frames are typically manufactured by stamping, and, in order to keep the lead frame shape intact, e.g., to avoid contact with each other during overmolding, each lead frame should be made wide and thick enough to maintain strength, and as a result, the pad pitch may be quite large, typically at least 0.4 mm.

[0100] Assembling the conductive leads 134 to the substrate 102, for example using a conductive adhesive or solder, may also require providing a groove 104 around each first conductive pad 106 to separate the conductive adhesive or solder from other components (e.g., from other components in the substrate), which may require a larger space in the substrate to assemble the conductive leads.

[0101] Furthermore, for example, if the module cap 130 is conductive, it may be desirable to isolate the conductive leads from the module cap. However, it may be difficult to isolate the conductive leads from the conductive module cap.

[0102] The inventors propose an optical sensor module that can overcome all or part of the above disadvantages, especially improve the electrical coupling between the substrate and the conductive components in the component or module cap, such as the electrical coupling between the substrate and the conductive traces in the glass.

[0103] Embodiments of the optical sensor module will be described below. These embodiments are non-limiting, and those skilled in the art will present various variations according to the instructions of this description.

[0104] In the following disclosure, unless otherwise stated, when referring to a component, it is meant to be an electronic component, and this includes conductive elements, such as conductive traces.

[0105] Figure 2A , Figure 2B and Figure 2C is a three-dimensional view of an optical sensor module 200 according to an embodiment. Figure 2B The connecting flexure of the optical sensor module is shown in more detail. Figure 2C The figure corresponds to the AA cross-sectional view of one of the connecting flexible members 230 .

[0106] Figure 2A , 2B and 2C optical sensor module 200 with Figure 1 The main difference of the optical sensor module 100 is that, instead of having conductive leads (e.g., a lead frame) assembled to the module cap 130, the optical sensor module 200 includes two connecting flexures 230 assembled to the module cap 130. The other elements of the optical sensor module 200 may be the same as those of the optical sensor module 100. Figure 1 The optical sensor module 100 is similar to: these elements have the same Figure 1 The same figure numbers are used in the drawings and the description is not repeated.

[0107] Each connection flexure 230 includes at least one metal layer covered by or encapsulated in at least one dielectric layer to electrically isolate the connection flexure from other conductive elements of the optical sensor module 200, except for a portion of the connection flexure where the at least one dielectric layer is opened to access the at least one metal layer for electrical connection. Thus, at the opened portion (e.g., end portion) of the connection flexure 230, the at least one metal layer is suitable for electrical coupling with a component of the optical sensor module 200.

[0108] exist Figure 2B and 2C In the example of FIG. 2 , each connection flexure 230 includes two metal layers, a first metal layer 232A and a second metal layer 232B, which are electrically isolated from each other by a dielectric core 231 .

[0109] For example, the first metal layer 232A and the second metal layer 232B are embedded in the dielectric core 231 , the first metal layer 232A is flush with the first surface 231A of the dielectric core, and the second metal layer 232B is flush with the second surface 231B of the dielectric core.

[0110] For example, the first and second metal layers 232A, 232B have a width smaller than that of the dielectric core 231 and are substantially centered relative to the dielectric core so that the first and second metal layers 232A, 232B do not reach the edge of the connection flexure 230. Therefore, the edge of the connection flexure 230 is electrically isolated.

[0111] For example, the first and second metal layers 232A, 232B form metal strips within the dielectric core 231 .

[0112] Each connection flexure 230 further includes two dielectric layers 233A, 233B: a first dielectric layer 233A covering the first metal layer 232A and a second dielectric layer 233B covering the second metal layer 232B. The first dielectric layer covers the surface of the first metal layer that is not isolated by the dielectric core, and similarly, the second dielectric layer covers the surface of the second metal layer that is not isolated by the dielectric core.

[0113] The first and second dielectric layers 233A, 233B may also at least partially cover the first and second surfaces of the dielectric core 231. Figure 2B and 2C As shown, the first and second metal layers 232A, 232B are embedded in the dielectric core 231 and have a width smaller than the width of the dielectric core 231 .

[0114] like Figure 2B and 2CAs shown, the first and second metal layers 232A, 232B can be coupled to each other at the first end 230A of the connection flexure 230 through a metal component 234, such as a metal button with a hole 235. The metal component 234 is preferably not covered by the first and second dielectric layers 233A, 233B, or at least partially not covered by the first and second dielectric layers 233A, 233B. The metal component 234 forms a conductive pad (second conductive pad) of the connection flexure 230.

[0115] The metal feature 234 (ie, the second conductive pad) may be coupled to one of the first conductive pads 106 of the substrate 102 by a conductive adhesive, such as conductive glue or conductive solder.

[0116] At the second end 230B of the connection flexure 230, the first dielectric layer 233A is opened to access the first metal layer 232A for electrical connection, so that the first metal layer 232A can be connected to the conductive trace 152, for example, through one of the third conductive pads 154. For example, the first metal layer 232A terminates in a fourth conductive pad 237, which is coupled to the third conductive pad 154, for example, through a conductive wire 155 formed by wire bonding. The conductive trace 152 corresponds to a component (first component) coupled to the substrate 102 through the connection flexure 230.

[0117] In one variation, each connection flexure 230 may be coupled to the conductive trace 152 of the glass 150 using a conductive adhesive or a conductive solder.

[0118] The second dielectric layer 233B may also be opened to access the second metal layer 232B for electrical connection. For example, the second metal layer 232B may also terminate in a conductive pad, or terminate in a fourth conductive pad 237 .

[0119] The dielectric material of the dielectric core and / or dielectric layer is, for example, polyimide. The advantage of polyimide is that it can be both thermosetting and thermoplastic and has high thermal stability. It also has excellent dielectric properties and an inherently low thermal expansion coefficient. In addition, polyimide can withstand high temperatures, such as those encountered during reflow, such as 500°C or higher.

[0120] The metal of the metal layer and / or the metal part connecting the flexure is, for example, copper.

[0121] In a variation, the two metal layers 232A, 232B may not be coupled to each other. For example, one of the two metal layers may be coupled to ground, while the other of the two metal layers may be dedicated to the conduction of electrical signals, such as Figures 5A to 5D as shown in the example.

[0122] In another variation, the connecting flexure may comprise only one metal layer, as described below. Figure 3B shown.

[0123] In another variant, the connecting flexure may comprise more than two metal layers, two adjacent metal layers being preferably isolated from each other by a dielectric material.

[0124] In one variation, instead of having two dielectric layers at each face of the connection flexure, the connection flexure may include a dielectric layer arranged to wrap or encapsulate the connection flexure.

[0125] Glass 150 may include, or be present in, a glass window, a lens or lenses, and / or a filter.

[0126] Each connection flexure 230 may be overmolded in the module cap 130 .

[0127] and Figure 1 Similar to the optical sensor module 100 of the optical sensor module 200, the module cap 130 of the optical sensor module 200 may be a plastic cap, and / or a molded cap formed of a molding material, such as a resin, a liquid crystal polymer (LCP), a polyamide, a nylon, or other engineering plastics. The module cap 130 may be formed using an injection molding method. In one variation, the module cap 130 may be conductive, such as a molded cap formed of a molding material (e.g., one of the above-mentioned molding materials) filled with conductive particles dispersed therein. When the module cap is conductive, it is advantageous to use a connecting flexure because the metal layer of the connecting flexure can be isolated from the conductive module cap by a dielectric layer and / or a dielectric core.

[0128] Examples of conductive module caps are described in more detail in French patent application 2311561 (law office number B22689), entitled “Modulede Capteur Optique,” ​​filed on October 25, 2023 in the name of STMICROELECTRONICS INTERNATIONAL NV, which is incorporated herein by reference to the maximum extent permitted by law.

[0129] Figure 2A and 2B Other features of the optical sensor module 200 may be similar to Figure 1 Other features of the optical sensor module 100.

[0130] In one variation, the optical sensor module may not include conductive traces, but may include one or more other components located on or under the glass and coupled to one or more connecting flexures.

[0131] In one variation, the optical sensor module may not include glass, but may include one or more components that are not positioned on or below the glass and are coupled to one or more connecting flexures.

[0132] In a variant that can be combined with the previous variants, one or more components can be located on the connecting flexible member. An example is as described below Figures 5A to 5D shown.

[0133] exist Figure 2A and 2B In FIG. 1 , two connection flexures are shown. This is not restrictive, and the optical sensor module may include one connection flexure. The optical sensor module may also include more than two connection flexures.

[0134] Figure 3A yes Figure 2B and 2C Schematic cross-sectional view of a connecting flexible member. Figure 3A The different layers of the connection flexure 230 are schematically shown, as well as a metal button 234 protruding from the rest of the connection flexure. Figure 3A Further shown are a first adhesion layer 236A between the first metal layer 232A and the first dielectric layer 233A, and a second adhesion layer 236B between the second metal layer 232B and the second dielectric layer 233B.

[0135] The thickness of the layer can vary. The thickness range is shown in Table 1 below as a non-limiting range.

[0136] [Table 1]

[0137] layer Thickness range (μm) 233A [10-100] or [20-50] 236A [10-100] or [20-50] 232A [10-50] or [15-35] 231 [10-100] or [20-50] 232B [10-50] or [15-35] 236B [10-100] or [20-50] 233B [10-100] or [20-50]

[0138] Figure 3B FIG. 1 is a schematic cross-sectional view of a connection flexible member 330 of an optical sensor module according to another embodiment. Figure 3A The connection flexure 230 differs primarily in that it includes only one metal layer 232A and no dielectric core. The metal layer 232A protrudes from the rest of the connection flexure 330, for example, to electrically couple to a substrate.

[0139] The thickness of the layer can vary. The thickness range is shown in Table 2 below as a non-limiting range.

[0140] [Table 2]

[0141] layer Thickness range (μm) 233A [10-100] or [20-50] 236A [10-100] or [20-50] 232A [10-50] or [15-35] 236B [10-100] or [20-50] 233B [10-100] or [20-50]

[0142] Figure 4A , Figure 4B , Figure 4C , Figure 4D , Figure 4E , Figure 4F , Figure 4G and Figure 4H It is shown in Figure 2A Top view and three-dimensional views of a method for assembling a connecting flexible member to a module cap in an optical sensor module.

[0143] Figure 4A 4 is a top view of a starting structure including 2D connection flexures 430. In each 2D connection flexure, a metal part 234 or a second conductive pad, a hole 235 in the metal part 234, and a fourth conductive pad 237 can be seen. In addition, each 2D connection flexure has a tab 432 that extends the 2D connection flexure 430 beyond the metal part 234 in order to facilitate the assembly method, in particular, to facilitate holding the connection flexure in a molding tool described below.

[0144] Figure 4B is a three-dimensional view of the structure obtained by bending the 2D connecting flexure 430 into the desired 3D shape required for subsequent molding, thereby forming the connecting flexure 230.

[0145] Figure 4C It is a three-dimensional view of the structure obtained by placing the connection flexible pieces 230 into a core 401 of a molding tool 400, which is suitable for positioning these connection flexible pieces relative to the future module cap, and by approaching a cavity 402 of the molding tool 400. The cavity 402 comprises a retaining insert 403, which is suitable for keeping the connection flexible pieces 230 in place during the subsequent molding process.

[0146] Figure 4D 4 is a three-dimensional view of the structure obtained when the mold cavity 402 and the mold core 401 are closed, wherein the retaining insert 403 holds the connecting flexible member 230 in its predetermined position. Figure 4B The retaining insert 403 shown in FIG. 4 is held in place for subsequent molding.

[0147] Figure 4E is a three-dimensional view of the structure obtained after the injection molding step, in which a molding material is injected into the mold cavity 402 to form the module cap 130 made of the molding material. After the injection molding step, the connection flexure 230 is overmolded in the module cap.

[0148] Figure 4F 4 is a three-dimensional view of the structure obtained after the molding tool 400 is opened, that is, after the mold core 401 and the mold cavity 402 are moved away from each other. When the molding tool is opened, the module cap 130 is ejected from the molding tool 400.

[0149] Figure 4Gis a top view of a structure obtained by cutting each connecting flexure 230 to remove the tab 432 .

[0150] Figure 4H is a three-dimensional view of the connection flexure 230 that is assembled to the module cap 130 and is over-molded into the module cap 130 .

[0151] Then, the module cap 130 assembled with the connection flexure 230 may be assembled to the substrate.

[0152] Figure 5A is a cut-away three-dimensional view of an optical sensor module 500 according to another embodiment. Figure 5B for Figure 5A FIG. 5 is a top view of the optical sensor module 500 . Figure 5C It shows Figure 5A and 5B FIG. 5 is a top view of details of the connecting flexure 530 of the optical sensor module 500 . Figure 5D is a cutaway three-dimensional view showing Figure 5C Details of the connecting flexure 530. Figure 5A Only means in Figure 5B The illustrated half of the optical sensor module 500 is cut along the BB direction.

[0153] and Figures 2A to 2C Similar to the optical sensor module 200, Figures 5A to 5D The optical sensor module 500 includes a module cap 130 and a glass 150 seated on a mount 139 formed in a first opening 131 of the module cap 130. The glass 150 includes a conductive trace 152 and a third conductive pad 154 coupled to each end of the conductive trace.

[0154] Figures 5A to 5D The optical sensor module 500 includes a connecting flexible member 530 .

[0155] The connecting flexure 530 is adapted to receive one or more components 503, 504 (second components) on itself, located below the glass 150. The at least one second component can be a light source 503 (such as a VCSEL), and optionally a photodiode 504, which can be used to monitor the light source 503. The at least one second element can be part of a light emitting device. This is not limiting, and other components can be positioned in the recess of the connecting flexure. Figure 5D Details of a light source 503, represented by a VCSEL, and details of a connecting flexure 530 on which the VCSEL 503 is mounted and coupled to the VCSEL 503 are shown.

[0156] In the example shown, the connection flexure 530 includes a recess 538 adapted to receive the components 503 , 504 beneath the glass 150 .

[0157] The connecting flexible member 530 includes a plurality of second conductive pads 534, which are adapted to be connected to a plurality of first conductive pads ( Figures 5A to 5D ) coupling is not shown.

[0158] The connection flexure 530 further includes a plurality of fourth conductive pads 537 adapted to be coupled to the conductive traces 152 through the third conductive pads 154 .

[0159] like Figure 5D As shown, the connecting flexure 530 includes a dielectric core 531, a first metal layer 532A on a first side of the dielectric core, a first dielectric layer 533A partially covering the first metal layer, a second metal layer 532B on a second side of the dielectric core, and a second dielectric layer 533B covering the second metal layer, which is connected to the dielectric core 531. Figure 2C and 3A The connecting flexure is similar, except that the first and second metal layers are not coupled to each other.

[0160] The recess 538 receiving the VCSEL 503 passes through the entire thickness of the first dielectric layer 533A and the first metal layer 532A to the dielectric core 531 .

[0161] The first metal layer 532A is dedicated to conducting electrical signals.

[0162] The first metal layer 532A terminates at each end 530A of the connection flexure 530 having a second conductive pad 534. For example, openings in the first and second dielectric layers 533A and 533B, the dielectric core 531, and the second metal layer 532B may allow the first metal layer 532A to be coupled to the first conductive pad of the substrate 102 through the second conductive pad 534.

[0163] At each end 530A of the connecting flexure 530, the first and second dielectric layers 533A, 533B of the connecting flexure 530 may include, for example may terminate with, a plurality of isolation elements 535, and each second conductive pad 534 may be interposed between a pair of isolation elements 535. The isolation elements may be finger-shaped.

[0164] The fourth conductive pad 537 may correspond to an opening in the first dielectric layer 533A in the top portion 530B of the connection flexure 530 to access the first metal layer 532A.

[0165] The first metal layer 532A can be divided into a plurality of metal traces electrically isolated from each other by a dielectric material, and each metal trace can be coupled to a dedicated second conductive pad 534. Therefore, different metal traces and second conductive pads can conduct different electrical signals. For example, at least the first metal trace of the first metal layer 532A is dedicated to the electrical signal conduction of the VCSEL 503.

[0166] The second metal layer 532B is suitable for coupling with ground.

[0167] The connecting flexure 530 further includes a bonding conductive pad 539, which is suitable for electrically coupling the components 503, 504 to the connecting flexure 530, for example, through the conductive wire 505 (wire bonding). Preferably, the bonding conductive pad 539 is in electrical contact with the first metal layer 532A, or terminates the first metal layer 532A, for example, through an opening in the first dielectric layer 533A in the top portion 530B of the connecting flexure 530, so that the components 503, 504 can be coupled to the first metal layer 532A, such as Figure 5D For example, using some of the conductive lines 505 , by bonding one of the conductive pads 539 , the VCSEL 503 is electrically coupled to the connection flexure 530 , and in particular, to the first metal layer 532A.

[0168] VCSEL 503 is located on third metal layer 506 in recess 538. Third metal layer 506 is electrically isolated from first metal layer 532A and electrically coupled to second metal layer 532B through at least one connecting via 507 (e.g., multiple connecting vias), and is therefore suitable for coupling to ground. Third metal layer 506 is preferably coplanar with first metal layer 532A.

[0169] It should be understood that the recess 538 receiving the photodiode 504 may be similar to the recess 538 receiving the VCSEL 503 , and the connection of the photodiode 504 to the connecting flexure 530 may also be similar to the connection of the VCSEL to the connecting flexure.

[0170] The connecting flexible member 530 comprises:

[0171] - two end portions 530A (end portions) configured to be connected to the substrate 102, a second conductive pad 534 and an isolation element 535 being defined in each of these end portions;

[0172] an upper portion 530B at least partially in contact with the inner surface 130B of the module cap 130 , in which a recess 538 is defined, as well as a fourth conductive pad 537 and a bonding conductive pad 539 ; and

[0173] - Two interconnecting portions 530C, each end portion 530A being connected to the upper portion 530B by one of the interconnecting portions 530C, each interconnecting portion being arranged substantially perpendicular to the upper portion.

[0174] Therefore, the connection flexible member 530 has a curved shape.

[0175] The connection flexure 530 allows for a plurality of second conductive pads 534 that are adjacent to each other and isolated from each other by isolation elements 535. Since the metal traces in the connection flexure 530 are isolated from each other by dielectric material, as are the second conductive pads 534, there is less risk of short circuits even if the connection flexure is deformed during molding. The pitch between the second conductive pads 534 can be up to one hundred microns.

[0176] Positioning the components on the connecting flexure allows the components to be closer to the glass than if the components were mounted on a substrate. In one example, the glass 150 is a lens, the component 503 is a light source such as a VCSEL, and the light from the light source can be divergent, for example, can have a cone shape. The greater the distance between the light source and the lens, the larger the lens size can be increased to cover the light cone, and conversely, the smaller the distance, the more the lens size can be reduced to cover the light cone. This also allows each component to be precisely positioned relative to the glass. In an example where the glass 150 is a lens and the component 503 is a light source such as a VCSEL, positioning the component on the connecting flexure can allow the lens to be well aligned relative to the VCSEL in three directions in space.

[0177] Figure 5D The advantages of connecting the flexure are shown. In fact, it can be observed that the distance d between the signal layer (first metal layer) and the ground layer (second metal layer) can be substantially stable, which allows to have a characteristic impedance and very good signal integrity. In addition, the signal layer can be very close to the ground layer, and the current loop (indicated by the dotted arrow) can be smaller, which can allow better electrical performance, such as better EMI performance.

[0178] The connection flexible member according to the embodiment also has other advantages, such as:

[0179] - Possibility to have high density of metal traces in metal layers;

[0180] - The metal layers in the connecting flexure, as well as the metal traces, can be insulated from the module cap, which is advantageous if the module cap is conductive;

[0181] - The connection flexure is flexible in design; parameters that can be adjusted include: the number of metal layers, each layer including one or more metal traces; the size, thickness and material of different layers; the shape of the dielectric layer; whether to use a dielectric core; the size and thickness of the connection flexure; whether to form a recess for receiving components... and so on.

[0182] One application of the embodiments is to manage the above-mentioned electromagnetic interference (EMI) through the first opening of the module cap using a conductive trace in the first opening and / or in the glass covering the first opening, for example by providing EMI reflection in the first opening. In such an application, a connecting flexure may be sufficient, for example to couple the conductive trace to ground.

[0183] Another application of an embodiment is for managing the safety issues mentioned above with light emitting devices, i.e., using conductive traces in the glass to detect whether the glass has been removed or otherwise separated from the module cap. When the glass is in place, the connecting flexure, the conductive wire, and the conductive trace form a conductive loop, such as through a conductive path in the substrate. However, if the glass becomes detached, the circuit in the conductive loop will be opened, the detection circuit can detect the open circuit, and the light emitting device can be disabled, for example. In such an application, it is usually necessary to have two connecting flexures to form the conductive loop.

[0184] A number of 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.

[0185] 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 herein.

Claims

1. An optical sensor module, comprising: A substrate including a first conductive pad; A module cap, assembled on the base plate; a connection flexure incorporated in the module cap, the connection flexure being adapted to electrically couple at least one of the first conductive pads to at least one component mounted on and / or within the module cap; and The connection flexure comprises at least one metal layer covered by or encapsulated in at least one dielectric layer.

2. The optical sensor module of claim 1, wherein: The connection flexure is over-moulded into the module cap; and / or The module cap is a conductive molded cap, for example, formed of a molding material including conductive particles dispersed therein.

3. The optical sensor module of claim 1 , wherein the at least one metal layer of the connecting flexure comprises, for example terminates in, a plurality of second conductive pads, the plurality of second conductive pads being adapted to be coupled with a plurality of first conductive pads of the substrate; and in, The at least one dielectric layer of the connection flexure comprises a plurality of insulating elements, for example terminates in a plurality of insulating elements, each second conductive pad being interposed between two insulating elements.

4. The optical sensor module of claim 1, further comprising a light emitting device, the module cap at least partially covering the light emitting device and comprising a first opening located above the light emitting device, the light emitting device being, for example, one of the at least one component.

5. The optical sensor module of claim 4 , further comprising glass, the glass being located in the first opening or between the first opening and the light emitting device, and / or covering the first opening, and being adapted to transmit an optical signal emitted by the light emitting device, the glass comprising a conductive trace corresponding to a first component of the at least one component, the connecting flexure being electrically coupled to the conductive trace, for example, by a conductive wire formed by wire bonding.

6. The optical sensor module of claim 1, wherein a second component of the at least one component is located on the connecting flexure.

7. The optical sensor module of claim 6, wherein the connection flexure comprises at least a recess adapted to receive the second component.

8. The optical sensor module of claim 7, wherein the connecting flexure comprises: at least one end portion configured to be connected to the substrate, a plurality of second conductive pads and a plurality of insulating elements being defined in the at least one end portion, and An upper portion at least partially contacts the inner surface of the module cap, the recess being defined in the upper portion.

9. The optical sensor module of claim 8, wherein the connecting flexure comprises two end portions and two interconnecting portions, wherein each end portion is connected to the upper portion via one of the interconnecting portions, and each interconnecting portion is disposed substantially perpendicular to the upper portion.

10. The optical sensor module of claim 8, wherein the connecting flexure comprises: a first metal layer electrically coupled to the second element, such as by a conductive line, the first metal layer being covered by a first dielectric layer of the at least one dielectric layer; a second metal layer configured to be connected to the ground, the second metal layer being covered by a second dielectric layer of the at least one dielectric layer; a third metal layer located in the recess and electrically isolated from the first metal layer, the second component being connected to the third metal layer, for example, being located on the third metal layer; a dielectric core interposed between the first metal layer and the second metal layer; and At least one connecting via is defined in the dielectric core and electrically couples the third metal layer to the second metal layer. 11 . The optical sensor module of claim 10 , wherein the recess passes through the entire thickness of the first dielectric layer and the first metal layer up to the dielectric core.

12. The optical sensor module of claim 8, wherein the connection flexure comprises a plurality of bonding pads defined on an upper portion of the connection flexure, each bonding pad being configured to be electrically coupled with the second component, for example, via a conductive line. 13 . The optical sensor module of claim 12 , wherein the plurality of bonding pads extend through the entire thickness of the first dielectric layer up to the first metal layer.

Images