WO2011090478A1

WO2011090478A1 - Printed circuit board with notch to permit circuitry protrusion

Info

Publication number: WO2011090478A1
Application number: PCT/US2010/021658
Authority: WO
Inventors: John P. Franz; Joseph R. Allen; Binh Nguyen
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2010-01-21
Filing date: 2010-01-21
Publication date: 2011-07-28

Abstract

A system comprises an upper printed circuit board (PCB) that comprises a notch. The system further comprises a lower PCB that electrically couples to the upper PCB, is disposed below the upper PCB and comprises circuitry that protrudes through the notch.

Description

PRINTED CIRCUIT BOARD WITH

NOTCH TO PERMIT CIRCUITRY PROTRUSION

BACKGROUND

[0001] Electronic components often are housed within a chassis. For instance, a server chassis or personal computer chassis may house components such as processors, memory and printed circuit boards (PCBs). These components' sizes may change over time for various reasons, including evolving industry standards and vendor design specifications. In many cases, such changes in component size may necessitate an undesirable increase in the size of the chassis within which the component is housed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] For a detailed description of embodiments, reference will now be made to the accompanying drawings in which:

[0003] Figure 1A illustrates a printed circuit board (PCB) assembly, in accordance with embodiments;

[0004] Figure 1 B shows a top-down view of a notch formed on a corner of a PCB, in accordance with embodiments;

[0005] Figure 1 C shows a perspective view of an illustrative interposer usable to electrically couple multiple PCBs in the assembly of Figures 1A, 2A and 3, in accordance with embodiments;

[0006] Figure 1 D shows a cross-sectional view of the interposer of Figure 1 C, in accordance with embodiments;

[0007] Figure 2A shows a front-end view of the PCB assembly of Figure 1A, in accordance with embodiments;

[0008] Figure 2B shows a perspective view of an upper PCB within the assembly of Figure 2A and further shows a plane coincident with the upper PCB, in accordance with embodiments;

[0009] Figure 2C shows a perspective view of part of the assembly of Figure 2A, in accordance with embodiments; and [0010] Figure 3 shows a front-end view of a chassis that houses, among other components, the PCB assembly of Figures 1A and 2A, in accordance with embodiments.

NOTATION AND NOMENCLATURE

[0011] Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to... ." Also, the term "couple" or "couples" is intended to mean either an indirect, direct, optical or wireless electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection or through an indirect electrical connection via other devices and connections.

[0012] The term "circuitry" refers to any apparatus or apparatuses capable of carrying electrical signals. In general, electronic devices, including the "memory connectors" and "memory cards" described herein, qualify as "circuitry."

[0013] Generally, when multiple articles are described herein as being "parallel" to each other, the articles lie along planes that are consistently equidistant from each other. This definition of the term "parallel" is not a strict one, however, and articles that lie along planes that are not consistently equidistant from each other may still be described as "parallel." For instance and without limitation, articles that lie along planes that intersect at an angle of five or fewer degrees may still reasonably be described as "parallel."

[0014] The term "notch" generally denotes a space that is bounded on two or more sides by a circuit board. For instance, a rectangular indentation on a side of a printed circuit board may be described as a "notch." Similarly, a rectangular indentation on a corner of a printed circuit board also may be described as a "notch." The term "rectangle" and derivatives thereof include squares and non- squares. Despite the foregoing definitions, notches are not limited to any particular shape or size. [0015] The terms "above" and "below" are used herein to describe relative positions of electronic components within a system. It is contemplated that when a first component in a system chassis is described as being "above" a second component in the system chassis, the chassis could be physically re-oriented so that the second component is "above" the first component. Thus, to avoid this possible ambiguity, the terms "above" and "below" are used with the assumption that any chassis containing components to which the terms refer is physically oriented in a manner that one of ordinary skill in the art would describe as "upright." At least some of the figures herein are described using the terms "above" and "below" to illustrate their precise meanings. The terms "upper," "lower," "top" and "bottom" should be similarly treated.

DETAILED DESCRIPTION

[0016] The following discussion is directed to various embodiments. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.

[0017] Disclosed herein are various embodiments in which electronic components inside a system chassis are arranged to increase the amount of space available within the chassis than would otherwise be possible. More specifically, a pair of printed circuit boards (PCBs) - referred to as the "upper PCB" and the "lower PCB" - are mechanically and electrically coupled so that the lower PCB is below the upper PCB and so that circuitry on the lower PCB passes through a notch in the upper PCB. This arrangement ensures that circuitry on the lower PCB does not reach the vertical height that it would otherwise reach if it were disposed on the upper PCB or on a PCB co-planar with the upper PCB. Arranging PCBs in this way "frees up" space within the system chassis so that additional components may be housed therein without increasing the size of the chassis. [0018] Figure 1A shows a perspective view of an upper PCB 102 and a lower PCB 104 in accordance with various embodiments. The upper PCB 102 and the lower PCB 104 both are housed within a chassis (specifically shown in Figure 3). When coupled as described below, the upper PCB 102 and the lower PCB 104 are generally parallel to each other. In some embodiments, the upper PCB 102 comprises various circuitry, such as central processing logic, additional processors, memory, resistors, capacitors, etc. In some embodiments, the upper PCB 102 comprises a "motherboard" and has the largest surface area of any PCB within the chassis.

[0019] The upper PCB 102 comprises a notch 106. In some embodiments, the notch is rectangular in shape and is formed at an edge of the upper PCB 102 so that the notch is bounded on three sides by the upper PCB 102 (like the notch 106 shown in Figure 1A). In some embodiments, the notch is rectangular in shape and is formed at a corner of the upper PCB 102 so that the notch is bounded on two sides by the upper PCB 102 (like the notch 106 shown in Figure 1 B). Notches need not be strictly rectangular and may be of any shape (e.g., any form of a quadrilateral). Notches may vary in size but, in at least some embodiments, are of the same or similar length as the lower PCB 104 and are of a width that is within a predetermined range (e.g., approximately 5 millimeters) of the width of the lower PCB 104. In some embodiments, the notch's "length" coincides with the edge of the upper PCB 102 at which the notch is formed. In some embodiments, the notch's "width" runs perpendicular to the edge of the upper PCB 102 at which the notch is formed.

[0020] The view of Figure 1A shows a top side 98 of the upper PCB 102. The processing logic, memory, resistors, etc. described above are disposed on this top side 98 of the upper PCB 102. The other side of the upper PCB 102 (not visualized) is referred to herein as the bottom side of the upper PCB 102. This bottom side of the upper PCB 102 may include, for instance, metal traces (not specifically shown) that facilitate the exchange of electrical signals between various circuitry disposed on the top side 98 of the upper PCB 102. In addition, metal contacts 108 are disposed on the bottom side of the upper PCB 102. These metal contacts 108 couple to the metal traces on the bottom side of the upper PCB 102. As shown in the example of Figure 1A, the metal contacts 108 span the length of the notch 106. As described below, these metal contacts 108 couple with metal contacts 1 16 on the lower PCB 104 so that data may be exchanged between circuitry on the upper and lower PCBs.

[0021] In addition to the metal contacts 108, in some embodiments, the upper PCB 102 comprises multiple orifices 1 10 (e.g., screw holes). These orifices 1 10 receive screws 1 1 1 or other such attachment devices on the lower PCB 104 so that the upper PCB 102 directly and mechanically couples to the lower PCB 104. Because the upper PCB 102 directly and mechanically couples to the lower PCB 104, the upper PCB 102 mechanically supports the lower PCB 104. The orifices 1 10 may be of any suitable size and shape. Although the orifices 1 10 are shown as being on the upper PCB 102 and the screws 1 1 1 as being on the lower PCB 104, in some embodiments, the orifice and screw positions may be switched so that the upper PCB 102 contains the screws 1 1 1 and the lower PCB 104 contains the orifices 1 10. Any and all such variations are included within the scope of this disclosure. Attachment techniques other than screws and orifices may be used (e.g., soldering procedures).

[0022] In at least some embodiments, the lower PCB 104 has a surface area that is smaller than that of the upper PCB 102. Any suitable circuitry may be disposed on a top side 96 of the lower PCB 104 (e.g., various electronics such as memory connectors and/or memory cards). The memory connectors 1 12 are capable of mating with memory cards 1 14 (or, more generally, any type of storage). The memory connectors 1 12 couple to metal traces (not specifically shown) which, in turn, couple to a plurality of metal contacts 1 16. These metal contacts 1 16 enable the transfer of electrical signals from circuitry on the PCBs 102 and 104. Specifically, signals are transferred from the memory cards 1 14 to the memory connectors 1 12 and then to the metal contacts 1 16 via metal traces. Signals may travel in the opposite direction as well.

[0023] In some embodiments, the metal contacts 108 and 1 16 couple so that they make direct, physical contact with each other. In some embodiments, however, the metal contacts 108 and 1 16 couple indirectly by way of an interposer 150, shown in Figure 1 C. The interposer 150 generally is any suitable device that is capable of transferring electrical signals between the metal contacts 108 and 1 16 when the metal contacts are not in direct, physical contact. In some embodiments, such as that shown in Figure 1 C, the interposer 150 comprises a plurality of metal contacts 152 disposed on multiple faces of the interposer 150. As shown, the interposer 150 comprises orifices 151 through which screws 1 1 1 (Figure 1A) may pass.

[0024] Figure 1 D shows a cross-sectional view of the interposer 150. The interposer 150 comprises a pair of non-conductive (e.g., plastic) surfaces 154a and 154b. The contacts 152 on the surface 154a transfer electrical signals to and from the contacts 152 on the surface 154b by way of conductors 156. The interposer 150 may be of any suitable length, width and thickness.

[0025] Figure 2A illustrates various embodiments. Specifically, Figure 2A shows a cross-sectional, front-end view of an assembly 200 comprising the upper PCB 102 and the lower PCB 104. The PCBs are generally parallel to each other. A central processing logic 202 is directly or indirectly disposed on a top side 98 of the upper PCB 102. In some embodiments, circuitry is disposed on a top side 96 of the lower PCB 104. In some embodiments, this circuitry comprises multiple memory connectors 1 12 that are disposed on the top side 96 of the lower PCB 104. In such embodiments, memory cards 1 14 plug into the memory connectors 1 12. The memory cards 1 14 may be of any suitable type.

[0026] The lower PCB 104 couples to the upper PCB 102 both electrically and mechanically at junction 204. As described above with respect to Figure 1A, at junction 204, metal contacts on the top surface of the lower PCB 104 electrically couple to metal contacts on a bottom surface of the upper PCB 102. These metal contacts may couple either directly or by way of an interposer 150 disposed between the metal contacts. Further, as mentioned, the lower PCB 104 mechanically couples to the upper PCB 102 using suitable connecting devices (e.g., screws). The upper PCB 102 thus mechanically supports the lower PCB 104.

[0027] In some embodiments, the upper PCB 102 is the lower PCB 104's sole mechanical support. Stated in another way, but for the upper PCB 102's mechanical support, the lower PCB 104 would fall. Stated in yet another way, but for the upper PCB 102's mechanical support, the lower PCB 104 would not be disposed at the vertical position at which it is disposed when the upper PCB 102 mechanically couples to the lower PCB 104. In some embodiments, the upper PCB 102 provides at least partial, but not full, mechanical support to the lower PCB 104. In some such embodiments, but for the upper PCB 102's mechanical support, additional strain would be placed upon any other mechanical support provided to the lower PCB 104.

[0028] The greatest dimensions of the upper PCB 102 - its length and width - are coincident with a plane 206. In some embodiments, at least one of the memory connectors 1 12 intersects this plane 206. In some embodiments, at least one of the memory cards 1 14 intersects this plane. In some embodiments, both (1 ) at least one memory connector 1 12 and (2) at least one memory card 1 14 intersect this plane. In some embodiments, all memory cards, if installed in memory connectors 1 12 on the lower PCB 104, intersect the plane 206. Figure 2B shows a perspective view of the upper PCB 102 and the plane 206. As indicated by axis legend 208, the plane 206 is coincident with the x- and y-axes but not with the z-axis.

[0029] Referring again to Figure 2A, as previously explained, the upper PCB 102 comprises a notch 106. The notch 106 is directly "above" the lower PCB 104. In some embodiments, at least one memory connector 1 12 extends past or passes or protrudes through the notch 106. In some embodiments, at least one memory card 1 14 extends past, or protrudes through, the notch 106. In some embodiments, both (1 ) at least one memory connector 1 12 and (2) at least one memory card 1 14 extend past or pass or protrude through the notch 106.

[0030] Figure 2C illustrates this protrusion aspect of the embodiments. As shown, the lower PCB 104 rests below the upper PCB 102 (and, thus, below the plane 206 of Figures 2A-2B). The notch 106 is directly above at least some of the lower PCB 104. The memory connectors 1 12, which rest on the lower PCB 104, protrude through the notch 106 such that the connectors 1 12 intersect the plane 206. As noted above, in some embodiments, the memory cards 1 14 may plug into the memory connectors 1 12 such that at least parts of the memory cards 1 14 also protrude through the notch 106 such that they intersect with the plane 206. As explained, in some embodiments, only the memory connectors 1 12 intersect the plane 206, and in some embodiments, only the memory cards 1 14 intersect the plane 206.

[0031] Figure 3 shows a front-end view of a chassis 300 housing the assembly 200 of Figures 2A and 2C. As shown, the assembly 200 comprises the upper PCB 102 and the lower PCB 104. The PCBs are generally parallel to each other. Memory connectors 1 12 are disposed on a top side 96 of the lower PCB 104 and memory cards 1 14 couple to the memory connectors 1 12. Central processing logic 202 is disposed on the top side 98 of the upper PCB 102. In addition, a heat sink 302 may be disposed atop the central processing logic 202 to help cool the central processing logic 202. In at least some embodiments, the heat sink 302 is sized so that its top edge 304 is generally flush (e.g., within 2 millimeters) with the top edges 306 of the memory cards 1 14.

[0032] As explained above, the upper PCB 102 comprises a notch 106 that is directly above the lower PCB 104. The memory connectors 1 12 are situated on the lower PBC 104 so that, when memory cards 1 14 are coupled to the connectors 1 12, the memory cards 1 14 protrude through the notch 106, as shown. In the embodiment shown in Figure 3, both the memory connectors 1 12 and the memory cards 1 14 protrude through the notch 106 where the memory cards 1 14 mate with the connectors 1 12. In some embodiments, the memory connectors 1 12 may be taller such that the memory cards 1 14 mate with the connectors 1 12 at a point above the plane 206 of the upper PCB 102. In such embodiments, only the memory connectors 1 12 are said to protrude through the notch 106. Conversely, in some embodiments, the memory connectors 1 12 may be shorter such that the memory cards 1 14 mate with the connectors 1 12 at a point below the plane 206 of the upper PCB 102. In such embodiments, only the memory cards 1 14 are said to protrude through the notch 106.

[0033] In any case, the arrangement of the upper and lower PCBs is such that the vertical elevations of the memory cards 1 14 - when mated to the connectors 1 12 - are lower than they would be if the connectors 1 12 were disposed on the upper PCB 102 or on a PCB co-planar with the upper PCB 102. Thus, the amount of free space above the memory cards 1 14 and the heat sink 302 is greater than it would otherwise be if the memory connectors 1 12 were disposed on the upper PCB 102 or on another PCB at the same vertical elevation as the upper PCB 102. Accordingly, additional hardware may be incorporated into the chassis 300 without increasing the size of the chassis 300. In the embodiment shown in Figure 3, a removable hard drive 305 is disposed above the memory cards 1 14 and the heat sink 302. The hard drive 305 blind-mates to a connector 308 (not explicitly visualized, but indicated by dashed lines). The top side 98 of the upper PCB 102 faces the connector 308, while the bottom surface of the upper PCB 102 faces the lower PCB 104.

[0034] Multiple instances of the upper-lower PCB arrangement described above may be implemented within a single chassis 300. For instance, as shown in Figure 3, the inclusion of an additional, removable hard drive 310 is made possible by disposing memory connectors 312 on another lower PCB 314. By mating memory cards 316 to connectors 312 on the lower PCB 314, the removable hard drive 310 can be blind-mated to connector 318.

[0035] As explained, although embodiments are described herein as including memory cards and connectors on a lower PCB, other circuitry - in lieu of or in addition to such memory cards and connectors - may be disposed on one or more of the lower PCBs. Further, the additional space created at the top of the chassis 300 by the PCB arrangements described herein may be filled by removable hard drives, non-removable hard drives or any other suitable removable or non-removable hardware.

[0036] In some embodiments, the upper PCB 102 has an approximate thickness of 2.5 millimeters. In some embodiments, the lower PCB 104 has an approximate thickness of 1 .5 millimeters. In some embodiments, a distance between the PCBs is approximately 1 .5 millimeters. In some embodiments, this distance between the PCBs is no more than 3 millimeters. In some embodiments, the distance between the lower PCB 102 and a bottom side 320 of the chassis 300 is approximately 0.25 millimeters. In some embodiments, the distance between the upper PCB 102 and the bottom side 320 of the chassis 300 is approximately 3.25 millimeters. In some embodiments, when a memory card 1 14 or 316 mates to a memory connector 1 12 or 312, the memory card 1 14 or 316 rests approximately 1 millimeter above the lower PCB 104. Each of the foregoing distances assumes a measurement between the two closest edges of the components involved. Each of the foregoing measurements may vary.

[0037] Terms such as "above," "below," "top," "bottom," "upper" and "lower" are used herein assuming that the chassis within which the PCBs are housed is oriented as shown in Figure 3. More specifically, the chassis 300 is normally oriented so that the bottom side 320 of the chassis is closer to the ground than the top side 322. For this reason, the PCB 102 is called the "upper" PCB, while the PCBs 104 and 314 are called the "lower" PCBs. For the same reason, the PCB 102 is said to be "above" the PCBs 104 and 314 and the PCBs 104 and 314 are said to be "below" the PCB 102. However, even if the chassis 300 is re-oriented so that the top side 322 is closer to the ground than the bottom side 320, the PCB 102 remains the "upper" PCB and the PCBs 104 and 314 remain the "lower" PCBs. Likewise, the PCB 102 remains "above" the PCBs 104 and 314 and the PCBs 104 and 314 remain "below" the PCB 102. The net effect of the foregoing definitions is that if any claim is infringed when a chassis is oriented one way, that claim is still infringed even if the chassis is re-oriented another way. Infringement cannot be avoided merely by re-orienting a chassis.

[0038] The above discussion is meant to be illustrative of various principles and embodiments. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. For example, while some of the foregoing techniques are described in context of the notch 106 shown in Figure 1A, the techniques may be adapted as necessary for application to the notch 106 shown in Figure 1 B. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

CLAIMS What is claimed is:

1 . A system, comprising:

an upper printed circuit board (PCB) that comprises a notch; and

a lower PCB that electrically couples to the upper PCB, is disposed below said upper PCB and comprises circuitry that protrudes through said notch.

2. The system of claim 1 , wherein a first group of electrical contacts disposed on said upper PCB and adjacent to said notch couples to a second group of electrical contacts disposed on the lower PCB.

3. The system of claim 1 , wherein the lower PCB directly and mechanically couples to said upper PCB.

4. The system of claim 1 , wherein said notch is at an edge of the upper PCB such that the notch is bounded on precisely three sides by the upper PCB.

5. The system of claim 1 , wherein said circuitry comprises a memory connector.

6. A system, comprising:

an upper printed circuit board (PCB) comprising a notch; and

a lower PCB that is mechanically supported by said upper PCB, is parallel to the upper PCB, and comprises circuitry that passes through said notch.

7. The system of claim 6, wherein electrical contacts adjacent to said notch electrically couple to electrical contacts on said lower PCB via an interposer.

8. The system of claim 6, wherein the upper PCB is disposed no more than 3 millimeters above the lower PCB.

9. The system of claim 6, wherein said notch is rectangular, is bounded on at least two sides by said upper PCB, and is bounded on no more than three sides by said upper PCB.

10. The system of claim 6, wherein said circuitry includes a memory connector, memory, or a combination of a memory connector and memory.

1 1 . A system, comprising:

an upper printed circuit board (PCB) comprising central processing logic; a lower PCB mechanically supported by and electrically coupled to the upper PCB, the lower PCB comprises storage that extends past a notch in said upper PCB; and

a connector capable of coupling to hardware that is removable from said chassis;

wherein a top side of the upper PCB faces the connector and a bottom side of the upper PCB faces the lower PCB.

12. The system of claim 1 1 , wherein the storage extends past said notch in the upper PCB such that the storage intersects a plane that is coincident with a greatest dimension of said upper PCB.

13. The system of claim 1 1 , wherein said central processing logic is disposed on said top side of the upper PCB.

14. The system of claim 1 1 , wherein said hardware comprises a removable hard drive.

15. The system of claim 1 1 , wherein the upper PCB has the greatest surface area among all PCBs in a chassis housing said upper and lower PCBs, and wherein said lower PCB is located below said upper PCB.