CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Serial

No. 62/030,982, filed July 30, 2014, which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present principles relate generally to electronic devices and, more particularly, to electronic devices having a radiofrequency tuner shield on a printed circuit board.

BACKGROUND ART

[0003] Consumer/market preference for set top boxes and the like (such as computers, game consoles, DVD players, CD players, etc.) is to have such devices be small/compact. However, this requirement is becoming increasingly challenging, because set top boxes and the like are required to perform more functions, which require more internal components. This results in more challenges to appropriately manage the heat which is potentially detrimental, in these devices. This also results in more challenges to appropriately shield components from the risk of electrostatic discharge and/or from interference (such as from radiofrequency radiation).

[0004] With the implementation of shielding such as the common closed polygon vertical wall metal structures that attach to printed circuit boards and surround at-risk components, some have employed shield covers that include heatsinks on the shield covers themselves to manage the heat which is potentially detrimental in these devices. In some of these devices, pins have been employed that go through the shield cover and into the printed circuit board (PCB) and then are soldered. In others of these devices, screws have been employed to secure the heatsink in place and make a ground connection to the PCB.

[0005] However, the devices that employ such shields with heatsinks tend to be items that are mass produced in high volume production environments. As such, the soldering shield covers and employing screws tend to be counterproductive in high volume production environments because they require not only some additional time in the production, but they also make rework and/or sample inspection operations more challenging. As such, the need exists for a shield cover with a heatsink and/or a shield cover with a heatspreader that is more efficient and designed to make rework and/or spot sample inspection operations easier.

[0006] Also, heatsinks can unfortunately be a good source for electrostatic discharge. This is especially the case for devices with antennae if the heatsink is too close to the antennae. This means that heat sink placement in crowded devices with antennae needs to be accurate, precise, and secure to ensure that in mass production heatsinks will not cause electrostatic discharge. Thus, any heatsink attachment schemes should be designed to ensure that the heatsinks are accurately, precisely, and securely attached without risk of shifting afterwards.

[0007] With the above challenges in mind and the increasing demand of the market for set top boxes to include a heatsink on top of shields that are on printed circuit boards, the present principles focus on effectively addressing the above mentioned needs.

SUMMARY OF THE PRESENT PRINCIPLES

[0008] The present principles include a method to ground and attach a heaksink to a metal shield cover of a metal shield assembly, which can be for radiofrequency shielding, quickly and easily for high volume production. Application of the present principles not only allows the heatsink to be assembled quickly for high volume production, but allows for quick removal of the shield cover from a lower shield structure for development work and printed circuit board repairs. [0009] An embodiment of the present principle is directed to a set top box that includes: an inner shield (39) that is attached on a printed circuit board (13) in which the inner shield is grounded to a ground contact (45) on the printed circuit board; a shield cover (38) that covers the inner shield, the shield cover having attachment apertures (40); and a heat extracting element (35) that is attached to the shield cover using one- way locking push pins (37) that engage the attachment apertures (40). Ythe one-way locking push pins can distort the attachment apertures such that the attachment apertures grip into the one-way locking push pins (37) to securely hold the heat extracting element on the shield cover. The heat extracting element can be grounded to the shield cover and the inner shield through the one-way locking push pins. The heat extracting element can include a planar base (41 ) having a bottom surface that faces the cover shield and a main heatsinking or heatspreading element (42) on the planar base opposite the bottom surface. The main heatsinking or heatspreading element can include a series of parallel fins or rails that extend perpendicularly upwards from the planar base. A thermal pad (43) can be positioned between the shield cover and the bottom surface of the planar base to facilitate thermal conduction from the inner shield and shield cover to the heat extracting element. The inner shield can include a plurality of vertical walls (60) having a bottom edge and a plurality of protruding pins (69) extending from the bottom and engaging openings in the circuit board to affix the inner shield to the circuit board. The attachment apertures of the shield cover prior to the oneway locking push pins engaging the attachment apertures can have a width in a first direction that is smaller than a width in the first direction of a portion of the one-way locking push pins that enters the attachment apertures.

[0010] Another embodiment of the present principle is directed to an electronic device that includes: an outer housing (28); a printed circuit board (13) within the outer housing; at least one electronic component (32) attached to a side of the printed circuit board; an inner shield (39) attached to the side of the printed circuit board, the inner shield having vertical walls (60) that surround the at least one electronic component; a shield cover (38) affixed to the inner shield in which the shield cover has attachment apertures (40); and a heat extracting element (35) attached to the shield cover by at least two screwless pins (37) in which the heat extracting element can be a heatsink or heatspreader. The screwless pins can be shorter than the vertical walls and can be spaced from the at least one electronic component and the printed circuit board. The screwless pins can be ring-shanked nails that irreversibly engage the attachment apertures of the shield cover or they can be one-way locking push pins. The heat extracting element can include a planar base (41 ) having a bottom surface that faces the cover shield, a main heatsinking element (42) on the planar base opposite the bottom surface in which the main heatsinking element is positioned in a central region of the planar base, and clearance apertures in peripheral regions of the planar base that contain the screwless pins. The heat extracting element can include only two of the clearance apertures that each contain one of the screwless pins in which the two clearance apertures are positioned at opposite corners of the planar base. The vertical walls of the inner shield can be horizontally oriented ridges (64) and the shield cover can include a top planar horizontal portion (71 ) to which the heat extracting element is attached, vertical side portions (72) extending downward from the top planar horizontal portion, and bent spring tabs (62) having a bent contact part (68) that engages the horizontally oriented ridges to secure the shield cover to the inner shield. The inner shield can include a plurality of protruding pins (69) extending from the bottom and engaging openings in the circuit board to affix the inner shield to the printed circuit board. The inner shield can be soldered to the printed circuit board such that the inner shield is grounded to a ground contact (45) on the printed circuit board. The attachment apertures of the shield cover prior to the screwless pins engaging the attachment apertures can have a width in a first direction that is smaller than a width in the first direction of a portion of the screwless pins that enters the attachment apertures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The invention will now be described by way of example with reference to the accompanying figures of which: [0012] Figure 1 shows perspective views of major components of a set top box according to the present principles;

[0013] Figure 2 shows a perspective disassembled view of the shield assembly and heatsink according to the present principles; [0014] Figure 3 shows a perspective assembled view of the shield assembly and heatsink according to the present principles;

[0015] Figure 4 shows various views of the attachment protocol of the heatsink to the shield cover according to the present principles;

[0016] Figure 5 shows a sectional assembled view of the shield assembly and heatsink according to the present principles;

[0017] Figure 6 shows a side view of the shield cover/heatsink assembly unattached from the shield according to the present principles;

[0018] Figure 7 shows views of the an embodiment of the spring of the shield cover according to the present principles; [0019] Figure 8 a perspective view of the heatsink;

[0020] Figure 9 is a flowchart outlining a method of assembling the electronic device according to the present principles; and

[0021] Figures 10 is another flowchart outlining a method of assembling the electronic device according to the present principles.

DETAILED DESCRIPTION OF THE PRESENT PRINCIPLES

[0022] The present principles can be directed to electronics devices such as set top boxes and the like as shown in Figure 1 . The set top box or the like having a shield and a heatsink can include the various components which are shown in Figure 1 . These components can be a main printed circuit board 13, a frame pan 18, and an outer cover 28.

[0023] Figure 1 A shows a main printed circuit board 13 or the like, which can be generally flat. The main printed circuit board 13 can have a main integrated circuit 17 or the like in a central region and holes 16 for mounting and/or securing the main printed circuit board 13 to a frame pan 18. Other features of the main printed circuit board are shown in the figure which can include jack panel connectors 15 at one edge and a button cluster 14 at another edge, which can be an opposing edge. The main integrated circuit and other heat generating or hot components 17 can contact a heat sink or heat spreader which is not shown. Also shown in Figure 1 A is a component 32 on the circuit board 13 which is at risk of overheating and/or interference. The component 32 is covered and shielded by a shield assembly 33 which is positioned on the circuit board over the component 32. The component 32 can be a collection of components and can be a tuner, for example. Arrow 36 shows the general positioning of the shield assembly 33 on the board 13 and over the component 32. Figure 1 A also shows a heatsink 35.

[0024] Figure 1 B shows an applicable lower chassis part or frame pan 18 which can have a rectangular shape and four sides and which can house or support the main printed circuit board (PCB) 13. The frame pan 18 can have a back wall 21 with jack panel apertures 19 to accommodate jack panel connectors 15 or the like and a base wall or base 22 that can have embosses 20 for the mounting or securing of the PCB 13 through the holes 16 therein. Additionally, the frame pan can have on the back wall 21 at least one connection feature 25 for engaging or attaching the pan frame in an outer cover 28.

[0025] Figure 1 C shows a housing or an outer cover 28 of the set-top box in an upright position. The orifices 29 are shown in the front side 30 which can be decorative. The orifices 29 are designed and aligned to accommodate the button cluster 14. The outer cover 28 further includes an upper wall 31 and two outer sides 34. The back wall 21 of the frame pan 18 can be the back of the outer cover 28 and the base 22 of the frame pan 18 can actually be the bottom exterior side of the outer cover 28. The assembled internal components of Figures 1 A-1 B in the final product are positioned in the outer cover 28.

[0026] Figure 2 shows a perspective disassembled view of the shield assembly

33 and heatsink 35. In this view, the shield assembly 33 is shown as comprising a shield cover 38 and a shield 39. The shield 39 can be a closed polygon vertical wall metal structure as shown that can have a ridge or ridges 64 on its vertical walls 60 which can protrude inward or outward from the vertical walls. The shield cover 38 can have a series of springs 62 extending downward from a peripheral edge of the top of the shield cover. The springs 62 can be designed to engage the ridge or ridges 64 to secure the shield cover 38 to the shield 39 to cover a component or components 32 (not shown in this view). The shield cover 38 can further include attachment apertures 40 for aligning and engaging the heatsink 35. The heatsink 35 as shown can include a planar base 41 from which a main heatsinking element or elements 42 extends upward. The heatsink elements 42 can be a series of vertically oriented parallel fins or can be other appropriate heatsinking elements such as a single block or series of blocks or a series of vertically oriented rods or rails. It should be noted that although the expressions heatsink and heatsinking are used throughout the specification, it is intended, unless expressly stated otherwise, that heatsink and heatsinking can also denote heatspreader and heatspreading, respectively.

[0027] The heatsink 35 can further includes an attachment part which can be a protruding part or pin 37 that engages the attachment apertures 40 of the shield cover 38 to securely attach the heatsink to the shield cover 38.

[0028] Also, as shown in Figure 2, a thermal pad 43 can be included between the shield assembly 33 and the heatsink 35 to facilitate thermal conduction from the shield assembly 33 to the heatsink 35.

[0029] Figure 3 shows a perspective assembled view of the shield assembly 33 and heatsink 35. In this view, the shield cover 38 is shown as being engaged on the shield 39 by the series of springs 62. The heatsink 35 is shown as being engaged on the shield cover 38 by the protruding parts or pins 37.

[0030] A feature of the present principle can include the grounding of the heatsink

35. This can be challenging because it is recognized by the inventor that the grounding of the heatsink can involve an attachment method which would make it difficult to remove the shield cover 38 after installation. Thus, an objective is to implement a ground protocol that effectively grounds the heatsink, but still allows the shield cover 38 to be removed for development work and PCB repairs. The ground pathway can include the shield 39 being grounded to a ground 45 on or near the PCB 13 as shown in Figure 4. The ground 45 can be in a region of the PCB 13 that (1 ) coincides with a part of the bottom edge of the vertical walls 60 of the shield 39 or a part of the bottom edge of the periphery of the shield 39 or (2) is a part of an opening in the PCB 13 to which a protruding pin or engaging part 69 of the shield 39 engages the opening in the PCB 13 for the attachment of the shield 39 to the PCB 13 by way of soldering or the like. As such, in a preferred embodiment, the heatsink has two small pins that are pressed tightly into the corners of a heatsink base 41 to make a good electrical connection to the shield cover 38. The pins 37 can be screwless and have a length shorter than the vertical walls 60 of the shield 39 such that the pins 37 do not touch nor contact the circuit board nor contents thereon. Hence, these pins 37 of the heatsink 35 are pressed into a one-way hole where the metal of the shield cover is deformed slightly to make a tight fit onto the pins. Thus, the pins 37 and heatsink 35 are securely attached and cannot be easily removed, because the edge regions of the metal shield cover in the vicinity of the pins 37 are deformed in one direction (i.e. in the pin insertion direction). The edge regions can tightly grip the pins, thereby causing the heatsink 35 to be securely attached in a non-reversible manner such that heatsink cannot be removed without damaging the metal shield cover 38. This secure attachment protocol also insures that the heatsink is in electrical contact with the shield cover. The shield cover 38 can also scratch and/or bite into the metal pin 37 of the heatsink, thereby, also making a reliable electrical connection. With this, the heatsink 35 and shield cover 38 are now firmly attached together and this heatsink 35/shield cover 38 assembly can be assembled and/or snapped to the shield 39 through the spring 62 grasping the ridges 64 and the heatsink 35/shield cover 38 can also be unassembled or unsnapped from the shield 39 without damage. The shield cover 38 is grounded and/or electrically connected to the shield 39 through the springs 62 touching the shield and/or the top portion 71 of the shield cover touching the shield.

[0031] Figures 4A-4D show various views of the attachment protocol of the heatsink 35 to the shield cover 38. The views also show how the heatsink 35 and shield 39 can be grounded by a protruding pin or engaging part 69 of the shield 39 that contacts a ground 45. The ground 45 can be part of a ground circuit (not shown) on the PCB 13. The pins 69 can be round or flat and can be part of a unitary vertical wall 60 of the shield 39. Figure 4A show a top plan view of the heatsink 35 on the shield cover 38. Figure 4B shows a side plan view of the heatsink 35 on the shield cover 38 along one side of the heatsink 35 in which the viewer is facing the long side of the outer fin 42. Figure 4C shows a cross section A-A cut along the heatsink 35/shield assembly 33 shown in Figure 4A to show how the pin 37 is engaged. Figure 4D is a magnified view of a section 80 of Figure 4C to more clearly show the preferred attachment mechanism. The pins 37 can be smooth or have rings/grooves. The pins 37 can be ring-shanked nails. Either way, the shield cover 38 locking feature can bite into the pin material making it practically impossible to remove without damage.

[0032] Figure 5 shows a sectional assembled view of the shield assembly and heatsink further highlighting the application of the pin 37. Figure 5 also shows how the pins 37 secure the heatsink 35 to the shield assembly 33 and how the shield cover 38 is secured to the shield 39. In this view, the pins 37 are positioned at opposite corners of the planar base 41 of the heatsink 35 in peripheral regions of the planar base 41 outside of the central region of the planar base 41 . The main heatsinking element or elements 42 are shown positioned in the central region. In this view, the interior side of the long side of the shield 39 can be seen. The view shows how the metal of the top portion 71 of the shield cover 38 around the attachment apertures 40 can be distorted as the pins 37 are pushed. Thus, one feature of the attachment apertures 40 is that prior to the entry of the pins 37, at least one horizontal dimension of the attachment aperture 40 in one direction is smaller than the thickness of the pin 37 in the same direction. With this relationship, the pin 37 can cause the metal around the attachment aperture 40 to distort. This is a distortion of the edge of the aperture in which the edge or edge region slightly bends downward and/or compresses outward to form an obtuse angle with the undistorted top portion 71 of the shield cover 38. The arrows in the vicinity of the pins 37 show the force applied to the pins to cause the engagement of the pins in the

attachment apertures 40.

[0033] Figures 5-7 shows how the springs 62 grasps the ridges 64. The spring 62 extend downward from the peripheral edge of the top of the shield cover 38. At a distal end of the spring 62, the spring can have a first bend inward such that an obtuse angle in formed between the inner surface of the proximal portion of the spring 62 with the inner surface of the first bend. From the first bend, the spring 62 can then have an a second bend outward in which the outer surface of the second bend will be at an obtuse angle with outer surface of the proximal portion of the spring 62. The inner bend of the spring 62 where the spring transitions from the first bend to the second bend can extend downward passed the ridge 64 grasps the ridge 64 as shown in Figure 5.

[0034] Figure 6 shows a side view of the shield cover 38/heatsink 35 assembly unattached from the shield 39. The view shows that the shield cover 38/heatsink 35 assembly can be removed for development, repair, or inspection purposes, because the shield cover 38/heatsink 35 assembly is attached as a single piece or assembly with the locking push pins 37. The view in Figure 6 also shows how the ground pathway can include the shield 39 being grounded to a ground 45 on or near the PCB 13 which can be through an aperture in the PCB 13.

[0035] In sum, the heatsink 35 being disposed over the shield assembly 33 provides a pathway for heat from the circuit board and the components thereon in the vicinity of the shield assembly 33. The heatsink 35 can be a generally flat horizontal base 41 and a series of vertically directed fins 42. The shield 39 can be substantially permanently attached to at least one of the bottom surface of the circuit board by solder or the like. Additionally, the shield 39 can comprise wrap-around bend tabs for attaching the shield to at least one of the bottom surface of the circuit board and the bottom frame of the electronic device. These wrap-around bend tabs can be the engaging parts 69 of of the shield 39. The heat sink can comprise a series of grooves inter-dispersed between the series of fins on a top side of the horizontal or planar base 41 . The series of grooves can assist in maximizing surface area, thereby increasing emissivity. In a particular embodiment, the heat sink 35 can cover over 50% of the top view surface area of the top of the shield cover 38. In another embodiment, the heat sink 35 can cover over 80% of the top view surface area of the shield cover 38. Of course, other percentages can also be used in accordance with the teachings of the present principles.

[0036] The present principles are applicable to systems which may need shielding from, for example, radio frequency (RF) emissions and heat sinking. The idea of merging the shield with the heat sink holders saves money and space. Further, having the shield cover and heatsink assembly constructed as described above makes removal this assembly for development, repair, or inspection of the components and/or the PCB within the shield 39 and the shield itself possible, because the shield cover and heatsink are attached together as one piece or assembly is together with the locking push pins. This removal of the shield cover/heatsink from the shield is thus possible without damage.

[0037] Other embodiments of the principles include further enhancing the RF shielding capability of the shield assembly by ensuring that there are minimal gaps 81 between the shield cover 38 with the heatsink 35 and the shield 39. As shown in Figure 7, the shield cover 38 comprises a top portion 71 that runs along or extends over the horizontal x-y plane and side portions 72 that extend from the periphery of the top portion and downward along the vertical z axis to overlap a part of the shield wall 60 in which the side portions contact the exterior side of the shield walls or are substantially close to the exterior side to ensure no gap therebetween or such a minimal spacing to ensure no direct path for EMI. In particular, this prevents a direct path around the shield walls. Additional features can be included which can be: spring tabs 62 extending from the side portions, the spring tabs comprise an upper bend part 65 that extends outward which can be an acute angle (or have an average acute angle if the part is curved) with the shield wall, a middle or second bend part 66 which can be an acute angle (or have an average acute angle if the part is curved) with the shield wall, and a contact part 68 at an end of the middle or second bend part 66; and a ridge 64 on the shield wall 60 that protrudes inward or outward from the shield wall 60, the ridge engages the contact part 68 to secure the shield cover to the inner shield. The contact part 68 applies an inward force 70 to help grip and secure the spring on the ridge.

[0038] Figure 8 show a perspective bottom view of the heatsink 35 having the thermal pad 43 attached to the bottom surface of the planar base 41 of the heatsink 35. In this view, the main heatsinking element or elements 42 are shown extending upward from the planar base 41 . Also in this view, pins 37 that engage the attachment apertures 40 of the shield cover 38 are shown being positioned in clearance apertures in the planar base 41 such that the head of the pins are over the aperture and the gripping ends of the pins 37 extend downward and protrude from the bottom surface of the planar base 41 so they can engage the attachment apertures 40 of the shield cover 38 to securely attach the heatsink to the shield cover 38.

[0039] Figure 9 is a flowchart outlining a method of assembling the electronic device according to the present principles. In step 901 , an RF shield 39 is provided having attachment ridges 64 on vertical walls 60 of the shield 39. In step 902, the RF shield 39 is positioned around a component or components 32 on the PCB 13 that need to be shielded. The RF shield 39 is then connected and grounded to the PCB 13. In step 903, a shield cover 38 is provided that has springs 62 for engaging ridges 64 and has attachment apertures 40 for aligning and engaging a heatsink 35. In step 904, the heatsink 35 is attached to shield cover 38 by pressing lock pins 37 through apertures in the heatsink through the attachment apertures 40 to securely and electrically attach heatsink 35 to shield cover 38. In this step, the pins 37 distort the attachment apertures 40 to lock the pins 37 and permanently bind the heatsink 35 to the shield cover 38. With the edges of the apertures 40 contacting the pins or biting into the pins 37, the heatsink 35 is electrically connected to the shield cover 38 through at least the lock pins 37. In step 905, the heatsink 35/shield cover 38 assembly is attached to the RF shield by downwardly pressing the heatsink 35/shield cover 38 assembly onto the shield 39 to permit the springs 62 to engage the ridges 64. In step 906, the housing that supports the PCB and the components thereon is then closed with the PCB and the components contained within the housing.

[0040] Figure 1 0 is another flowchart outlining a method of assembling the electronic device according to the present principles. In step 1001 , an RF shield 39 is provided having attachment ridges 64 on vertical walls of the shield 39. In step 1002, the RF shield 39 is positioned around a component or components 32 on the PCB 13 that need to be shielded. The RF shield 39 is then connected and grounded to the PCB 13. In step 1003, a shield cover 38 is provided that has springs 62 for engaging ridges 64 and has attachment apertures 40 for aligning and engaging a heatsink 35. In step 1004, the shield cover 38 is attached to the RF shield by downwardly pressing the shield cover 38 assembly onto the shield 39 to permit the springs 62 to engage the ridges 64. In step 1005, the heatsink 35 is attached to the RF shield cover 38 by downwardly pressing the heatsink 35 onto the shield cover 38. In this step, the pins 37 distort the attachment apertures 40 to lock pins 37 and permanently bind the heatsink 35 to the shield cover 38. With the edges of the apertures 40 contacting the pins or biting into the pins 37, the heatsink 35 is electrically connected to the shield cover 38 through at least the lock pins 37. In step 1006, the housing that supports the PCB and the components thereon is then closed with the PCB and the components contained within the housing.

[0041] Although the illustrative embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the present principles are not limited to those precise embodiments, and that various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope of the present principles. All such changes and modifications are intended to be included within the scope of the present principles as set forth in the appended claims.

[0042] Also, it is intended that expressions such as "back" and "front," "top" and bottom," and "vertical" and "horizontal," as well as other complementary terms are intended to be construed from the perspective of the observer of the figures; and as such, these expression can be interchanged depending upon the direction that the observer looks at the device.