Optical sensor with integrated leadframe cap

Abstract

The invention relates to an optical sensor with an integrated lead frame cap. The electronic device includes: a substrate including a first contact pad; a cap including a front surface, the cap attached to the surface of the substrate, the front surface including a first recess and a second recess located within the first recess, the cap including a first lead frame embedded within the cap; a first device mounted over the cap and located within the second recess; and an optical lens mounted over the cap and the first device, where a first end of the first lead frame extends out of the cap and is electrically connected to the first contact pad, and where a second end of the first lead frame extends out of the cap at the front surface and is electrically connected to the first device.

Description

Technical Field

[0001] The present invention relates generally to sensor integration systems and methods, and in particular embodiments, to leadframe caps for integrating optical sensors. Background Art

[0002] Optical sensors are commonly incorporated into a variety of products, such as consumer electronics (e.g., headphones, earbuds, mobile phones, watches, and laptops) as well as automotive systems and security equipment. In particular, various types of optical sensors can be used for ranging, depth profiling, 3D imaging, and medical imaging, among others. One of the key manufacturing process steps for optical sensors is the packaging step, where the individual electronic components of the optical sensor are integrated onto a substrate. A constant trend in manufacturing is to reduce packaging costs while maintaining or improving sensor performance, as well as reducing package assembly steps and package wiring. Summary of the invention

[0003] According to one embodiment of the present invention, an electronic device includes: a substrate including a first contact pad; a cap including a front surface, the cap being attached to the surface of the substrate, the front surface including a first recess and a second recess located within the first recess, the cap including a first lead frame embedded in the cap; a first device mounted on the cap and located within the second recess; and an optical lens mounted on the cap and the first device, wherein a first end of the first lead frame extends out of the cap and is electrically connected to the first contact pad, and wherein a second end of the first lead frame extends out of the cap at the front surface and is electrically connected to the first device.

[0004] According to one embodiment of the present invention, an electronic device includes: a substrate including a plurality of contact pads; a cap including a front surface, the cap being attached to the surface of the substrate, the front surface including a higher level, an interlayer level, and a lower level; a plurality of lead frames embedded in the cap, wherein one end of each lead frame extends out of the cap at the bottom surface of the cap and is electrically connected to one of the plurality of contact pads, and wherein the other end of each lead frame extends out of the cap at the upper portion of the cap; a first device mounted on the lower level and electrically connected to a first lead frame and a second lead frame among the plurality of lead frames; and an optical lens mounted on the interlayer level and located above the first device.

[0005] According to one embodiment of the present invention, a method for manufacturing an electronic device includes: forming a first lead frame; using an injection molding process to form a plastic cap, the plastic cap having side walls and a front surface and surrounding the first lead frame, so that one end of the first lead frame is located at the front surface, and the other end of the first lead frame is located at the bottom surface of one of the side walls, the end of the first lead frame is exposed, and the front surface of the plastic cap includes a first recess; mounting the plastic cap on a substrate; and mounting a first device on the front surface of the plastic cap and in the first recess. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0007] Figure 1 A perspective view showing a conventional design of an optical sensor module;

[0008] Figure 2 shows a top view of an example lead frame sandwich cap housing a light source and optical elements of an optical sensor module according to various embodiments;

[0009] Figure 3 shows a cross-sectional view of an example lead frame sandwich cap housing a light source and optical elements of an optical sensor module according to various embodiments;

[0010] Figure 4 shows a perspective view of an example lead frame sandwich cap housing a light source, optical elements, and reference detector of an optical sensor module according to various embodiments;

[0011] Figure 5 Shown before accommodating the optical element Figure 4 Another perspective view of an example lead frame sandwich cap;

[0012] Figure 6 shows a perspective view of another example lead frame sandwich cap housing a light source, an optical element, and a reference detector of an optical sensor module according to another embodiment;

[0013] Figure 7 A perspective view of a leadframe structure showing an example leadframe sandwich cap for an optical sensor module according to various embodiments;

[0014] Figure 8 a top view of a leadframe structure showing an example leadframe sandwich cap for an optical sensor module according to various embodiments; and

[0015] Figure 9A-9B A process flow diagram of a method of manufacturing an example lead frame sandwich cap for an optical sensor module according to various embodiments is shown, wherein Fig. 9A An embodiment is shown. Fig. 9B Another embodiment is shown. DETAILED DESCRIPTION

[0016] The present application relates to sensor integration systems and methods, and more specifically to the introduction of a lead frame sandwich cap into an optical sensor module. For certain sensor applications (e.g., time-of-flight proximity sensors), an optical sensor module may typically include a light source (e.g., a laser) and an optical detector, both of which may be mounted and packaged on a substrate. The light source emits light, and a portion of the emitted light is reflected from objects in the environment to be sensed and picked up by the optical detector. In order to accommodate the different focal lengths of the transmitter and receiver and to avoid undesirable crosstalk between these two elements, the light source may be positioned at a higher level in the sensor module than the optical detector on the substrate. For example, such a design may be achieved by inserting a spacer block below the light source, and providing electrical connections via a flat flexible cable (FFC), such as Figure 1 However, such a design generally requires a large footprint for the FFC, and its manufacturing process may be complicated. Therefore, a new design of an optical sensor module that does not use the FFC may be desired.

[0017] In various embodiments of the present disclosure, a lead frame sandwich cap is used for an optical sensor module (e.g., a time-of-flight proximity sensor) in which a light source can be mounted above the cap so that it is at a higher level than an optical detector. In the present disclosure, the cap can be referred to as a lead frame sandwich cap because it includes a lead frame structure embedded within the body of the cap, and the cap also has a sandwich level (i.e., a recessed surface below the uppermost surface) to accommodate the light source and optional other components (e.g., an optical lens). The electrical connection of the light source can advantageously be provided by the lead frame embedded within the cap, thereby eliminating the need for at least some of the FFCs in the conventional design. Therefore, this new cap design can allow for a reduction in the footprint of the optical sensor module and a simplified manufacturing process. In addition, in some embodiments, the optical sensor module can include other elements (e.g., an optical lens and a reference detector), and the lead frame structure including multiple lead frames can also be electrically connected to them individually. The lead frame sandwich cap can be designed to securely mount these other elements near the top of the lead frame sandwich cap.

[0018] In the following, we first refer to Figure 1 The conventional design of an optical sensor module with a light source is described. Then, according to reference Figure 2-Figure 8 Various embodiments are described to describe the design of a lead frame sandwich cap integrated into an optical sensor module. An example process flow chart for manufacturing a lead frame sandwich cap is shown in FIG. Figure 9A-9B . All drawings in this disclosure are for illustration purposes only and are not drawn to scale, including the aspect ratios of features. Although the following description in this disclosure is primarily directed to a lead frame sandwich cap and a light source mounted on the cap, the optical sensor module may include various other components (e.g., optical detectors) on the same substrate or elsewhere.

[0019] Figure 1 A perspective view showing a conventional design of an optical sensor module.

[0020] The conventional design of an optical sensor module is briefly described below. The optical sensor module may have two parts: an optical sensor part 102 and a light source part 104. The two parts may typically have different focal lengths, and there is a risk of crosstalk between the different optical components. To compensate for this difference in focal length and to minimize crosstalk, the components within the light source part 104 may be lifted by a spacer block 110, and a flat flexible cable (FFC) 120 may be used for electrical connection. In addition, to facilitate device component integration, it may also be desirable to match the top surfaces of the light source part 104 and the optical sensor part 102. Disadvantages of this design include a large footprint of the FFC 120, a complex manufacturing process and increased cost, and a dead zone caused by the spacer block 110.

[0021] Figure 2 and Figure 3 An example lead frame sandwich cap 210 housing a light source 230 and an optical element 240 of an optical sensor module according to various embodiments is shown, wherein Figure 2 A top view is shown, and Figure 3 A cross-sectional view is shown.

[0022] In various embodiments, the lead frame interlayer cap 210 is mounted on the substrate 200 as part of the optical sensor module 20. It should be noted that Figure 2 and Figure 3 Only a portion of the optical sensor module 20 is shown, and in various embodiments, other components (e.g., optical detectors) may be present on or elsewhere on the substrate 200. In various embodiments, the substrate 200 may include a printed circuit board (PCB). In one embodiment, the substrate 200 may be a PCB made of FR-4 glass reinforced epoxy laminate. Figure 2 and Figure 3 Only a portion of the substrate 200 is shown in FIG. Various electrical components of the optical sensor module 20 may be mounted on the substrate 200 and electrically connected to each other using, for example, wire bonding.

[0023] In various embodiments, such as Figure 2 As shown in the top view of FIG. 2 , the lead frame sandwich cap 210 may have a square or rectangular shape, but in other embodiments, it may have any other reasonable shape. The lead frame sandwich cap 210 may include sidewalls 215 and a front surface 220, such as Figure 3, such that they define a cavity 212 below the front surface 220. In the present disclosure, the "front" face or surface and the "bottom" face or surface of the lead frame sandwich cap 210 are used only to describe the relative positions relative to the substrate to which the lead frame sandwich cap 210 can be mounted, where the bottom face faces the substrate and the front face faces away from the substrate. The sidewalls are any faces or surfaces other than the front face or surface, or the bottom face or surface, and may or may not be clearly present in the lead frame sandwich cap 210 (for example, they may not be clearly distinguishable when the cap has an oval shape). Therefore, it should be noted that depending on the mounting orientation and configuration of the optical sensor module, any face of the lead frame sandwich cap 210 may be considered the front surface 220, without being limited to Figure 2-Figure 8 In various embodiments, the cavity 212 defined by the lead frame sandwich cap 210 can have a height h relative to the front surface of the substrate 200, and in one embodiment, the height h can be between 0.1 mm and 10 mm. The height h can be selected to enhance the positioning of one or more components (e.g., a light source) mounted above the lead frame sandwich cap 210. In one embodiment, one of the components can be located between 0.1 mm and 10 mm above the front surface of the substrate 200.

[0024] although Figure 2 Although not specifically described, the cavity 212 can be further divided into two or more spaces separated by one or more partition walls. The partition walls can be internal components of the lead frame sandwich cap 210 and can provide additional structural support for the front surface within the cavity 212 or provide optical isolation.

[0025] The lead frame sandwich cap 210 can receive the light source 230 above the front surface 220. The front surface 220 can include a recessed surface so that one or more components can be mounted so that the final state of the optical sensor module 20 can have a relatively flat surface. Figure 3 As shown, the front surface 220 may further include a first recessed surface 222 (sandwich level) and a second recessed surface 224 (lower level), wherein the second recessed surface 224 is lower and within the first recessed surface 222. In one or more embodiments, the light source 230 may be accommodated within the area of ​​the second recessed surface 224, and the optical element 240 may be positioned above the light source 230 and accommodated within the areas of the first recessed surface 222 and the second recessed surface 224.

[0026] like Figure 3 As shown, the optical element 240 may be located above the light source 230 and cover the entire light source 230. Figure 2 Only the front surface of optical element 240 can be seen.

[0027] although Figure 3An embodiment of a lead frame sandwich cap having two recesses (i.e., a sandwich level and a lower level) is shown, but in other embodiments, additional recesses may be present. For example, the lead frame sandwich cap 210 may include three or more recesses (e.g., an upper level, a middle level, a lower level). In one embodiment, the light source 230 may be disposed at a lower level, the optical element 240 may be disposed at a middle level, and the optical baffle may be disposed at an upper level. The optical baffle may protect the wire bonds connected to the optical element 240. In some embodiments, the optical baffle may also include an aperture.

[0028] In various embodiments, the light source 230 may include a vertical cavity surface emitting laser (VCSEL) for the optical sensor module 20, and the optical element 240 may include an optical lens through which light (e.g., laser light from the VCSEL) passes. In other embodiments, the light source 230 may include a light emitting diode (LED) or an edge emitting laser (EEL). In some embodiments, the optical element 240 may also include a filter. Although Figure 2 and Figure 3 A single light source and a single optical element are shown in FIG, but the lead frame sandwich cap 210 can accommodate multiple light sources or optical elements. For example, in one embodiment, an array of VCSELs can be used. The number and footprint of the recesses of each level of the lead frame sandwich cap 210 can be selected according to the design of the optical sensor module 20.

[0029] In one embodiment, the entire optical element 240 may be located within the recessed area of ​​the front surface 220, and no portion of the optical element 240 may protrude from the leadframe interlayer cap 210. In another embodiment, the top of the optical element 240 may protrude from the leadframe interlayer cap 210.

[0030] In various embodiments, the leadframe sandwich cap 210 may also include a leadframe structure to provide electrical connections for various components (eg, the light source 230). Figure 2 , two lead frames (a first lead frame 214 and a second lead frame 216) are shown as examples, but in other embodiments, any number of lead frames are possible. In some embodiments, the lead frame structure is mostly embedded in the body of the lead frame sandwich cap 210, except for the ends of each lead frame used for electrical connection. In one or more embodiments, some additional portions of the lead frame structure other than its ends may also be exposed, which can help prevent deformation during the manufacture of the lead frame sandwich cap 210 (e.g., an injection molding process). The exposed portion of the lead frame structure can be advantageously used to attach a heat sink directly to the interior of the lead frame structure within the cavity 212.

[0031] like Figure 2As shown, one end (lower end) of the first lead frame 214 may extend out of the lead frame interlayer cap 210 at the bottom surface of the lead frame interlayer cap and be electrically connected to a contact pad on the substrate 200. Although not specifically shown, in a top view, the lower end of the first lead frame 214 may be connected to the contact pad without protruding from the outline of the lead frame interlayer cap 210.

[0032] The other end (upper end) of the first lead frame 214 may extend out of the lead frame interlayer cap 210 within the recessed area of ​​the front surface 220 and be electrically connected to the light source 230. Figure 2 As shown, bonding wires 232 may be used to connect the upper end of the first lead frame 214 to the top of the light source 230 .

[0033] Similarly, one end (lower end) of the second lead frame 216 may extend out of the lead frame interlayer cap 210 at the bottom surface of the lead frame interlayer cap and be electrically connected to a contact pad on the substrate 200. In some embodiments, the lower end may not protrude from the outline of the lead frame interlayer cap 210 in a top view.

[0034] The other end (upper end) of the second lead frame 216 may extend out of the lead frame interlayer cap 210 in the recessed region of the front surface 220 (eg, near the second recessed surface 224) and be electrically connected to the light source 230. Figure 2 As shown, in one embodiment, the upper end of the second lead frame 216 can be directly connected to the bottom of the light source 230 without wire bonding, but in other embodiments, bonding wires or other methods can be used. In one embodiment, the electrical connection between the second lead frame 216 and the light source 230 can be made at the top of the light source 230. The type and configuration of the electrical connection between the light source 230 and the corresponding lead frame are not limited to Figure 2 As shown, and can be selected according to the specific application and design of the optical sensor module 20.

[0035] In various embodiments, the body of the leadframe sandwich cap 210 may include a plastic material, and the leadframe structure may include a conductive material, such as copper. The leadframe sandwich cap 210 may be manufactured using an injection molding process. For example, in an example manufacturing process, a leadframe structure may be first formed, and a thermoplastic material may be molded into a target shape of a cap surrounding the leadframe structure using injection molding (e.g., overmolding). In some embodiments, more than one individual leadframe may be formed in multiple or individual pieces, aligned to one another according to a target configuration, and overmolded.

[0036] Using plastic for the body of the lead frame sandwich cap 210 can advantageously make the cap opaque so that the cavity 212 and the light source 230 can be optically isolated. This advantageously prevents any light from the light source from entering the cavity 212 where other optically sensitive components may be present. The material used for the body of the lead frame sandwich cap 210 is also non-conductive.

[0037] In various embodiments, the optical sensor module 40 is part of a time-of-flight sensor and may further include a detector assembly 250 on the substrate 200. The detector assembly 250 may include various elements necessary for optically detecting a portion of the emitted light from the light source 230. For example, the detector assembly 250 may include a single photo avalanche diode (SPAD) array as a detector system. In addition, the detector assembly 250 may further include a cap for accommodating the detector on the substrate 200. In one embodiment, the lead frame interlayer cap 210 may be made large enough to accommodate the detector assembly 250, wherein the detector assembly 250 and the cavity 212 may be separated by a partition wall inside the lead frame interlayer cap 210.

[0038] Figure 4 A perspective view of an example lead frame interlayer cap 410 housing the light source 230 and the optical element 240 of the optical sensor module 40 is shown in accordance with various embodiments.

[0039] refer to Figure 4 , according to some embodiments, further describes a modified design of the lead frame sandwich cap 410. The light source 230 and the optical element 240 can be connected with Figure 2 and Figure 3 Same as described in. Figure 4 As shown, Figure 3 Unlike the straight sidewall 215 that is vertical from top to bottom in the embodiment, the lead frame sandwich cap 410 in these embodiments may have a sidewall 415 with a step. The sidewall step may be designed so that the top of the lead frame sandwich cap 410 has a smaller footprint than the bottom. Figure 4 In the embodiment, the sidewall 415 has two steps on at least one face of the lead frame sandwich cap 410, but in other embodiments, the sidewall can have various other shapes and designs. In addition, the sidewall thickness of the lead frame sandwich cap 410 can be relatively constant. The shape of the lead frame sandwich cap 410 can be adjusted accordingly according to the requirements in various sensor applications, such as the size and desired position of the various components to be installed (e.g., the light source 230 and the optical element 240) and the cavity inside the lead frame sandwich cap 410. This flexibility in designing and manufacturing the lead frame sandwich cap 410 can advantageously help minimize the use of plastic and / or the size of the optical element 240 and maximize the volume of the cavity.

[0040] Figure 4The lead frame interlayer cap 410 in the embodiment has a front surface 420, which further includes three recessed surfaces at height positions: a first recessed surface 422, a second recessed surface 424, and a third recessed surface 426, wherein the third recessed surface 426 is at Figure 4 The light source 230 may be disposed on the third concave surface 426, and the optical element 240 may be disposed on the second concave surface 424. An optical baffle (not shown) may be disposed on the first concave surface 422.

[0041] Still reference Figure 4 , the leadframe sandwich cap 410 can include two additional leadframes that form secure trace connections 412 for the optical element 240. In certain embodiments, these secure trace connections 412 may be desirable because they can be used to check for proper installation and presence of the optical element 240. In addition to their ends, these additional leadframes can also be embedded within the body of the leadframe sandwich cap 410. For example, one end (lower end) of the additional leadframe can extend out of the leadframe sandwich cap 410 at the bottom surface of the leadframe sandwich cap and be electrically connected to the contact pads on the substrate 200. The other end (upper end) of the second leadframe 216 can extend out of the leadframe sandwich cap 410 inside the recessed area of ​​the top surface and be electrically connected to the optical element 240.

[0042] As previously Figure 1 As shown, conventional designs may use spacers to mount the light source, and the spacers may have a considerable footprint on the substrate. In contrast, the use of a lead frame sandwich cap 410 may occupy only a small portion of the front surface of the substrate 200 and leave space for mounting various components. Therefore, in various embodiments, within the cavity defined by the lead frame sandwich cap 410, the optical sensor module 40 may also include additional electrical components 450 mounted on the substrate 200. Examples of additional electrical components 450 include, but are not limited to, passive components (e.g., inductors, capacitors, and resistors), laser drivers, and electrically erasable programmable read-only memories (EEPROMs).

[0043] Figure 5 The optical element 240 is shown before being accommodated. Figure 4 Another perspective view of an example lead frame sandwich cap 410. The optical element 240 is Figure 5 , in order to illustrate other components underneath.

[0044] In various embodiments, in addition to the light source 230 and the optical element 240, the lead frame sandwich cap 410 may also accommodate additional components, such as a reference detector 510. In certain embodiments, the reference detector may include a photodiode configured to optically sense the state of the light source 230. Having a reference detector advantageously enables monitoring and checking the proper performance of the optical sensor module 40, in particular the light source 230. Detection by the reference detector may also be used for time-of-flight analysis. In one or more embodiments, the reference detector 510 may include a single photo avalanche diode (SPAD) array. In certain embodiments, the reference detector 510 or other components may be mounted above the lead frame sandwich cap 410 in a recessed area of ​​the front surface 420, for example, at the same level as the light source 230. In other embodiments, the reference detector 510 may be positioned at any level below the optical element 240. In one embodiment, the reference detector 510 may be mounted on the substrate 200. In various embodiments, the lead frame sandwich cap 410 may include one or more additional lead frames, which are Figure 5 In one or more embodiments, one or more of the lead frames connected to the light source 230 may also be connected to the reference detector 510, thereby minimizing the number of additional lead frames used for the reference detector 510.

[0045] In certain embodiments, such as Figure 5 As shown, a bond wire 512 may be used to connect the upper end of an additional lead frame (which may be a reference detector cathode lead frame 514) to the top of the reference detector 510. In various embodiments, more than one bond wire may be used for electrical connection to the reference detector 510. In one embodiment, the reference detector anode lead frame (in Figure 5 The upper end of another additional lead frame (not visible in FIG. 1 ) can be directly connected to the bottom of the reference detector 510 without wire bonding, but in other embodiments, bonding wires or other methods can be used. In addition, in one embodiment, both the cathode and anode of the reference detector 510 can be located at the top and can be connected to the corresponding lead frame using bonding wires.

[0046] Still refer to Figure 5 In one embodiment, one or more bonding wires 532 can be used to connect the light source cathode lead frame 535 to the top of the light source 230, and the light source anode lead frame 534 can be directly connected to the bottom of the light source 230 without wire bonding, but in other embodiments, bonding wires or other methods can be used.

[0047] The types and configurations of electrical connections between the various electrical components (eg, reference detector 510, light source 230, and optical element 240) and the corresponding lead frames are not limited to Figure 4-Figure 5As shown, instead, it can be selected according to the specific application and design of the optical sensor module 40.

[0048] although Figure 4-Figure 5 , but in other embodiments, the electrical components described above may be positioned differently, and the front surface 420 may include three or more recessed surfaces. In one embodiment, the light source 230, the reference detector 510, the optical element 240, and the optical baffle may be positioned at four different height levels from bottom to top. The optical element 240 may cover both the light source 230 and the reference detector 510, respectively, and the optical baffle may cover the optical element 240 and at least a portion of the wire bonding for the optical element 240.

[0049] Figure 6 A perspective view of another example lead frame sandwich cap 610 housing a light source, optical elements, and reference detector of an optical sensor module according to another embodiment is shown.

[0050] exist Figure 4-Figure 5 In the prior embodiment shown, the reference detector 510 and the light source 230 are mounted on the same level within the recessed region of the lead frame interlayer cap 410, and both face upward. In other embodiments, the reference detector 510 may be positioned differently, but still within the recessed region of the lead frame interlayer cap 410. Such a configuration may advantageously help reduce the size of the optical components and thereby help reduce the manufacturing cost of the optical sensor module.

[0051] exist Figure 6 In the embodiment, the recessed area of ​​the lead frame sandwich cap 610 may have an opening 615 connecting the recessed area and the cavity 612 in the lead frame sandwich cap 610. The opening 615 may allow a portion of the light from the light source 230 reflected back at the surface of the optical element 240 to enter the cavity. Therefore, the reference detector 510 may be installed in the cavity 612. In one or more embodiments, as shown in FIG. Figure 6 As shown, the reference detector 510 can be mounted on the inner surface of the lead frame sandwich cap 610 and face downward. Therefore, the additional lead frames for the reference detector 510 can be arranged so that their upper ends extend outward inside the cavity 612 so that they can be easily connected to the reference detector 510.

[0052] Figure 7 A perspective view of a leadframe structure of an example leadframe sandwich cap 710 of an optical sensor module 70 is shown in accordance with various embodiments. Figure 8 Shows Figure 7 A top view of the lead frame structure.

[0053] As previously mentioned, in various embodiments, the leadframe structure of the leadframe sandwich cap may include any number of leadframes, and these leadframes may be integrated as part of the leadframe sandwich cap. Figure 7 and Figure 8 , an example of a lead frame sandwich cap 710 having six lead frames is shown. For illustration purposes, the body (e.g., a plastic body) of the lead frame sandwich cap 710 is illustrated only with the lines of its frame to make the lead frames embedded in the body visible. Figure 7 and Figure 8 In the figure, the lead frame sandwich cap 710 has a light source anode lead frame 534, a light source cathode lead frame 535, a reference detector anode lead frame 714, a reference detector cathode lead frame 715, a first safety trace lead frame 721 and a second safety trace lead frame 722.

[0054] As previously described, each lead frame can be embedded in the body of the lead frame sandwich cap 710, except for its ends. In various embodiments, each lead frame can be designed to provide an electrical connection between a component mounted at a lower level and another component mounted at a higher level (e.g., at any level near the top surface of the lead frame sandwich cap 710). Therefore, one end (lower end) of each lead frame can be electrically connected to a contact pad on the substrate 200. The other end (upper end) of each lead frame can be electrically connected to a component mounted above the lead frame sandwich cap 710.

[0055] exist Figure 7 and Figure 8 In one embodiment, four lead frames (light source anode lead frame 534, light source cathode lead frame 535, reference detector anode lead frame 714, and reference detector cathode lead frame 715) are connected to one end of substrate 200, while the other two lead frames (first safety trace lead frame 721 and second safety trace lead frame 722) are connected to the opposite end of substrate 200. In an alternative embodiment, the lead frames may have the same Figure 7 and Figure 8 Different connection points to the substrate 200 are shown, depending on the available footprint on the substrate 200 and the cap design and location of components above the leadframe interlayer cap.

[0056] In addition, the upper end of each lead frame can be positioned according to the position of the corresponding component to be connected. In various embodiments, since the optical element can be positioned above the light source and the reference detector, the two lead frames for the optical element (the first safety trace lead frame 721 and the second safety trace lead frame 722) can have an upper end that is positioned higher than the upper ends of the other four lead frames (the light source anode lead frame 534, the light source cathode lead frame 535, the reference detector anode lead frame 714, and the reference detector cathode lead frame 715). In some embodiments, the upper end of the set of light source anode lead frame 534 and light source cathode lead frame 535 can be positioned at the same level as the upper end of the set of reference detector anode lead frame 714 and reference detector cathode lead frame 715, but in other embodiments, considering the optical configuration of the light source and the reference detector, they can be at different levels.

[0057] Although Figure 7 and Figure 8 Six lead frames are shown, but in some embodiments, some of the lead frames may be optional and omitted from the optical sensor module. In one embodiment, the optical element may be mounted without the security trace feature and thereby Figure 7 and Figure 8 The first safety trace lead frame 721 and the second safety trace lead frame 722 in the embodiment may be omitted. In another embodiment, the reference detector may be optional, and thus Figure 7 and Figure 8 The reference detector anode lead frame 714 and the reference detector cathode lead frame 715 may be omitted.

[0058] Figure 9A-9B A process flow diagram illustrating a method of manufacturing an example lead frame sandwich cap for an optical sensor module according to various embodiments is shown.

[0059] exist Fig. 9A In the process flow 90, the first lead frame is formed (block 900), followed by forming a plastic cap (block 910) using an injection molding process (e.g., using a thermoplastic material), so that the plastic cap can have side walls and a front surface, and surround the first lead frame, wherein one end of the first lead frame is at the front surface, and the other end of the first lead frame is at the bottom surface of one of the side walls, the end of the first lead frame is exposed, and the top surface of the plastic cap includes a first recess. Subsequently, the plastic cap can be mounted on a substrate (block 920), and then a first device (e.g., a light source, such as a vertical cavity surface emitting laser VCSEL) can be mounted on the top surface of the plastic cap and in the first recess (block 930).

[0060] In some embodiments, the substrate may include contact pads and solder, and mounting the plastic cap on the substrate may also directly form an electrical connection between the first device and one end of the first lead frame. In other embodiments, the electrical connection may be formed separately after mounting the plastic cap by, for example, solder jetting.

[0061] exist Fig. 9B , another process flow 92 begins with the same steps of forming a first lead frame (block 900) and a plastic cap (block 910) as described above. After these steps, a first device may first be mounted on the top surface of the plastic cap (block 930), and then the plastic cap carrying the first device may be mounted on a substrate (block 920).

[0062] The use of injection molding (e.g., overmolding) allows the manufacture of the lead frame sandwich cap to be flexible, and any reasonable design and shape can be manufactured relatively easily without requiring a large amount of additional cost. In addition, the injection molding process can also be used to manufacture multiple plastic parts with or without a portion of the lead frame structure embedded inside, and then assemble these plastic parts to form the final lead frame sandwich cap.

[0063] The lead frame sandwich cap as described above in various embodiments can provide various advantages over conventional sensor integration methods. First, the lead frame sandwich cap can elevate the position of the light source and optical elements relative to the detector, thereby minimizing the risk of crosstalk. Second, by embedding the lead frame into the cap, at least a portion of the spacer blocks and flat flexible cables (FFCs) often used in conventional designs can be removed. This can advantageously reduce manufacturing costs and free up some floor space on the substrate. The free space on the substrate can be used to install other components. Third, the lead frame sandwich cap can be added at minimal additional cost. This is because, in certain optical sensor applications where strong lasers can be used, a housing cap covering an optical element (e.g., an optical lens) may already be required to limit the light path for safety reasons. Since the lead frame sandwich cap can be implemented by modifying an already required housing cap, it can be introduced into the optical sensor module without a completely new component.

[0064] Exemplary embodiments of the present invention are summarized here. Other embodiments may also be understood from the entirety of the specification and the claims submitted herein.

[0065] Example 1. An electronic device comprising:

[0066] a substrate including a first contact pad;

[0067] a cap including a front surface, the cap being attached to a surface of the substrate, the front surface including a first recess and a second recess, the second recess being located within the first recess, the cap including a first lead frame, the first lead frame being embedded within the cap;

[0068] a first device mounted on the cap and located in the second recess; and

[0069] an optical lens mounted on the cap and the first device,

[0070] wherein a first end of the first lead frame extends out of the cap and is electrically connected to the first contact pad, and

[0071] The second end of the first lead frame extends out of the cap at the front surface and is electrically connected to the first device.

[0072] Example 2. The electronic device of Example 1, wherein the first device comprises a vertical cavity surface emitting laser (VCSEL).

[0073] Example 3. An electronic device according to any one of Examples 1 or 2, wherein the entirety of the optical lens is placed within the first recess.

[0074] Example 4. The electronic device according to any one of Examples 1 to 3 further includes a second device disposed on the cap.

[0075] wherein the cap further comprises a second lead frame, wherein the second lead frame is embedded in the cap,

[0076] wherein a first end of the second lead frame extends out of the cap and is electrically connected to a second contact pad of the substrate, and

[0077] The second end of the second lead frame extends out of the cap at the front surface and is electrically connected to the second device.

[0078] Example 5. An electronic device according to any one of Examples 1 to 4, wherein the first device is a light source for emitting light, and wherein the second device includes a photodiode configured to optically sense a state of the first device by detecting a portion of the light emitted from the light source.

[0079] Example 6. The electronic device of any one of Examples 1 to 5, wherein the cap further comprises a third lead frame, the third lead frame being embedded in the cap,

[0080] wherein the first end of the third lead frame extends out of the cap and is electrically connected to a third contact pad of the substrate, and

[0081] The second end of the third lead frame extends out of the cap at the front surface and is electrically connected to the optical lens.

[0082] Example 7. An electronic device comprising:

[0083] a substrate including a plurality of contact pads;

[0084] a cap including a front surface, the cap being attached to a surface of the substrate, the front surface including an upper level, an interlayer level, and a lower level;

[0085] a plurality of lead frames embedded in the cap, wherein one end of each lead frame extends out of the cap at a bottom surface of the cap and is electrically connected to one of the plurality of contact pads, and wherein the other end of each lead frame extends out of the cap at an upper portion of the cap;

[0086] a first device mounted on the lower level and electrically connected to a first lead frame and a second lead frame of the plurality of lead frames; and

[0087] An optical lens is mounted on the interlayer level and is located above the first device.

[0088] Example 8. The electronic device according to Example 7 further includes a wire connecting the first device and the first lead frame among the multiple lead frames, wherein the first device is directly mounted on one end of the second lead frame among the multiple lead frames to provide an electrical connection.

[0089] Example 9. The electronic device of any one of Examples 7 or 8 further includes a second device mounted above the lower level and electrically connected to a third lead frame and a fourth lead frame of the plurality of lead frames.

[0090] Example 10. An electronic device according to any one of Examples 7 to 9, wherein the optical lens is electrically connected to a fifth lead frame and a sixth lead frame of the plurality of lead frames.

[0091] Example 11. An electronic device according to any one of Examples 7 to 10, wherein the front surface of the cap includes an opening, and the electronic device further includes a second device, which is mounted inside the cap, at the upper portion of the cap, and is electrically connected to a third lead frame and a fourth lead frame among the multiple lead frames.

[0092] Example 12. An electronic device according to any one of Examples 7 to 11, wherein the first device includes an upward-facing vertical cavity surface emitting laser (VCSEL), and wherein the second device includes a photodiode that faces downward and is configured to optically sense a state of the VCSEL.

[0093] Example 13. An electronic device according to any of Examples 7 to 12, wherein the first device is positioned between 0.1 mm and 10 mm above the surface of the substrate.

[0094] Example 14. The electronic device of any one of Examples 7 to 13 further includes an optical sensor mounted on the surface of the substrate, the optical sensor being enclosed within the cap.

[0095] Example 15. A method of manufacturing an electronic device, the method comprising:

[0096] forming a first lead frame;

[0097] forming a plastic cap using an injection molding process, the plastic cap having side walls and a front surface and surrounding the first lead frame, such that one end of the first lead frame is located at the front surface, and the other end of the first lead frame is located at a bottom surface of one of the side walls, the end of the first lead frame is exposed, and the front surface of the plastic cap includes a first recess;

[0098] mounting the plastic cap onto a substrate; and

[0099] A first device is mounted on the front surface of the plastic cap and within the first recess.

[0100] Example 16. The method of Example 15, further comprising: electrically connecting the first device to the one end of the first lead frame.

[0101] Example 17. A method according to any one of Examples 15 or 16, wherein the front surface of the plastic cap also includes a second recess, the second recess is larger than the first recess, and the first recess is located within the second recess, and the method further includes: installing an optical lens on the front surface of the plastic cap and within the second recess, wherein the optical lens is disposed above the first device.

[0102] Example 18. The method according to any one of Examples 15 to 17, further comprising:

[0103] forming a second lead frame, wherein the plastic cap is formed to surround the second lead frame so that one end of the second lead frame is located at the front surface and the other end of the second lead frame is located at the bottom surface of one of the side walls, and the end of the second lead frame is exposed; and

[0104] The first device is electrically connected to the one end of the second lead frame.

[0105] Example 19. The method of any one of Examples 15 to 18, wherein mounting the plastic cap onto the substrate forms a cavity defined by the plastic cap and the substrate, the cavity being optically isolated from the first device.

[0106] Example 20. The method of any one of Examples 15 to 19 further includes: mounting another electrical component on the substrate, wherein after the plastic cap is mounted on the substrate, the other electrical component is surrounded by the plastic cap.

[0107] Example 21. A method according to any one of Examples 15 to 20, wherein the first device comprises an upward-facing vertical cavity surface emitting laser (VCSEL), the method further comprising: mounting a second device onto the plastic cap, the second device comprising a photodiode configured to optically sense a state of the VCSEL.

[0108] Example 22. The method of any one of Examples 15 to 21, wherein the first device comprises a laser, the method further comprising: mounting an optical sensor on top of the substrate.

[0109] Although the present invention has been described with reference to illustrative embodiments, this description should not be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments and other embodiments of the present invention will be apparent to those skilled in the art with reference to the description. As an illustration, Figure 1-9B The embodiments described in the foregoing may be combined with each other in further embodiments. Therefore, the appended claims are intended to cover any such modifications or embodiments.

Claims

1. An electronic device, comprising: a substrate including a first contact pad; a cap including a front surface, the cap being attached to a surface of the substrate, the front surface including a first recess and a second recess, the second recess being located within the first recess, the cap including a first lead frame, the first lead frame being embedded within the cap; a first device mounted on the cap and located in the second recess; and an optical lens mounted on the cap and the first device, wherein a first end of the first lead frame extends out of the cap and is electrically connected to the first contact pad, and The second end of the first lead frame extends out of the cap at the front surface and is electrically connected to the first device. 2 . The electronic device of claim 1 , wherein the first device comprises a vertical cavity surface emitting laser (VCSEL). 3 . The electronic device according to claim 1 , wherein the entirety of the optical lens is placed in the first recess.

4. The electronic device according to claim 1, further comprising a second component, the second component being disposed on the cap, wherein the cap further comprises a second lead frame, wherein the second lead frame is embedded in the cap, wherein a first end of the second lead frame extends out of the cap and is electrically connected to a second contact pad of the substrate, and The second end of the second lead frame extends out of the cap at the front surface and is electrically connected to the second device.

5. The electronic device of claim 4, wherein the first device is a light source for emitting light, and wherein the second device comprises a photodiode configured to optically sense a state of the first device by detecting a portion of the light emitted from the light source.

6. The electronic device according to claim 1, wherein the cap further comprises a third lead frame, the third lead frame being embedded in the cap, wherein the first end of the third lead frame extends out of the cap and is electrically connected to a third contact pad of the substrate, and The second end of the third lead frame extends out of the cap at the front surface and is electrically connected to the optical lens.

7. An electronic device comprising: a substrate including a plurality of contact pads; Cap, including a front surface, the cap being attached to a surface of the substrate, the front surface comprising an upper level, an interlayer level, and a lower level; a plurality of lead frames embedded in the cap, wherein one end of each lead frame extends out of the cap at a bottom side of the cap and is electrically connected to one of the plurality of contact pads, and wherein another end of each lead frame extends out of the cap at an upper portion of the cap; a first device mounted on the lower level and electrically connected to a first lead frame and a second lead frame of the plurality of lead frames; as well as An optical lens is mounted on the interlayer level and is located above the first device.

8. The electronic device according to claim 7 further comprises a wire connecting the first device and the first lead frame of the plurality of lead frames, wherein the first device is directly mounted on one end of the second lead frame of the plurality of lead frames to provide an electrical connection. 9 . The electronic device of claim 7 , further comprising a second device mounted on the lower level and electrically connected to a third lead frame and a fourth lead frame of the plurality of lead frames. 10 . The electronic device of claim 7 , wherein the optical lens is electrically connected to a fifth lead frame and a sixth lead frame of the plurality of lead frames.

11. The electronic device according to claim 7, wherein the front surface of the cap includes an opening, and the electronic device further includes a second device, which is installed on the inner side of the cap at the upper portion of the cap and is electrically connected to a third lead frame and a fourth lead frame among the plurality of lead frames.

12. The electronic device of claim 11, wherein the first device comprises an upward-facing vertical cavity surface emitting laser (VCSEL), and wherein the second device comprises a photodiode, the photodiode facing downward and configured to optically sense a state of the VCSEL.

13. The electronic device of claim 7, wherein the first device is positioned between 0.1 mm and 10 mm above the surface of the substrate.

14. The electronic device of claim 7, further comprising an optical sensor mounted on the surface of the substrate, the optical sensor being enclosed within the cap.

15. A method of manufacturing an electronic device, the method comprising: forming a first lead frame; forming a plastic cap using an injection molding process, the plastic cap having side walls and a front surface and surrounding the first lead frame so that one end of the first lead frame is located at the front surface and the other end of the first lead frame is located at a bottom side of one of the side walls, the end of the first lead frame is exposed, and the front surface of the plastic cap includes a first recess; installing the plastic cap onto the substrate; as well as A first device is mounted on the front surface of the plastic cap within the first recess.

16. The method according to claim 15, further comprising: The first device is electrically connected to the one end of the first lead frame.

17. The method according to claim 15, wherein the front surface of the plastic cap further comprises a second recess, the second recess is larger than the first recess, the first recess is located within the second recess, the method further comprising: An optical lens is mounted on the front surface of the plastic cap within the second recess, the optical lens being disposed over the first device.

18. The method according to claim 15, further comprising: forming a second lead frame, wherein the plastic cap is formed to surround the second lead frame so that one end of the second lead frame is located at the front surface and the other end of the second lead frame is located at the bottom side of one of the side walls, the end of the second lead frame being exposed; as well as The first device is electrically connected to the one end of the second lead frame.

19. The method of claim 15, wherein mounting the plastic cap onto the substrate forms a cavity defined by the plastic cap and the substrate, the cavity being optically isolated from the first device.

20. The method of claim 15, further comprising: Another electrical component is mounted on the substrate, wherein the other electrical component is surrounded by the plastic cap after the plastic cap is mounted on the substrate.

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