WO2000008722A1

WO2000008722A1 - Moisture resistant electrical connector for a cellular telephone

Info

Publication number: WO2000008722A1
Application number: PCT/US1999/016022
Authority: WO
Inventors: Shawn M. Stephenson; William H. Jennings; Mark W. Weadon; Stacy Smith; Brad Kreschollek
Original assignee: Ericsson, Inc.
Priority date: 1998-08-05
Filing date: 1999-07-14
Publication date: 2000-02-17
Also published as: AU5214199A; MY119862A; US6227872B1

Abstract

The cellular telephone of the present invention includes a generally sealed, moisture resistant electrical external connector that resides in the wall of the phone housing and provides a series of electrically conductive pathways which lead from the external surface of the housing, through the housing wall, to designated areas on an internally located printed circuit board. More particularly, these electrically conductive pathways or contacts, that essentially penetrate the cellular telephone housing, are incorporated within the housing wall via an insert molding, press fitting, or similar process such that a generally sealed, moisture resistant barrier is formed between the individual contacts which comprise the connector and the surrounding housing.

Description

MOISTURE RESISTANT ELECTRICAL CONNECTOR FOR A CELLULAR TELEPHONE

FIELD OF THE INVENTION

The present invention relates to electrical connectors for use with hand-held cellular

telephone units, and more particularly to a system connector that incorporates electrical

contacts directly into the housing of a telephone in a manner such that the connector is sealed

with respect to the external environment.

BACKGROUND OF THE INVENTION

System connectors associated with cellular telephones are used to establish and

maintain electrical connection between the internal circuitry of the telephone and an external

electrical circuit or device. Examples of such external devices and connection requirements

are battery charging equipment and base or docking stations typically employed in

automobiles to permit hands-free operation of the cellular telephone unit. In the case of

charging units, the telephone unit must incorporate external electrical power contacts that

provide access to the associated on-board battery pack. The ability to dock with a hands-free

base station requires, at a minimum, that the telephone unit incorporate sufficient external

electrical contacts to facilitate transfer of the necessary data from the internal circuitry of the

telephone unit to the associated base station.

Historically, such system connectors presented openings or pathways for water and

debris to freely enter the interior compartment of the telephone. Typically, these penetration

pathways are present in the telephone unit because there are several separate components, including a printed circuit board, a structural frame member, and a housing enclosure that

must be assembled, none of which are sealed prior to assembly. As such, system connectors

are generally comprised of separate pieces that are either soldered directly to the printed

circuit board or are pressed onto the printed circuit board with the housing and frame aligning

around them.

In addition to the concerns for totally sealing the cellular telephone, it is also desirable

to provide a system connector that can be easily and efficiently electrically coupled to the

printed circuit board. Typically, system connectors, sometimes herein referred to as external

connectors, are often connected to the printed circuit board by hand or reflow soldering. In

some instances, the external connector is attached to the front cover of the cellular telephone

with an adhesive and then the external connector and the printed circuit board are

interconnected with a flex film assembly. There are shortcomings and drawbacks to both of

these approaches. With respect to hand soldering, this is expensive because most operations

are done manually. Further, yields tend to be low due to operator error and the varying skill

levels found among workers. Reflow soldering operations are difficult to manage because of

the large size of the external connector. With respect to utilizing a flex film assembly, this

approach adversely affects the overall size of the cellular telephone. In the end, the flex film

assembly requires more space and that translates into a larger cellular telephone. In addition,

it is expensive to assemble flex film because flex film assemblies are not generally

automatable. Finally, utilizing an approach where the external connector is permanently

attached to the printed circuit board results in additional tolerance concerns between the

external connector contact and the housing of the cellular telephone. This adversely affects the tolerance stack up between accessories that^' attach to the housing of the cellular telephone

and their mating system connector contacts. In the end, overall component tolerances must be

held tighter, and this, of course, increases cost. As a result, one finds that the overall package

design of the cellular telephone suffers. To accommodate these large tolerances, the

packaging size of the cellular telephone necessarily increases.

Therefore there remains the need for a waterproof or sealed system connector for

cellular telephone units that can be manufactured and implemented easily and inexpensively,

which eliminates the risk of moisture penetration and subsequent damage to the internal

electrical components that comprise the telephone. In addition, there is a need for a system

connector design that forms an integral part of the housing structure of the cellular telephone

which is capable of automated assembly, with the system connector being designed to

interface with the printed circuit board through pressure contacts rather than soldered contacts.

SUMMARY OF THE INVENTION

The present invention entails a cellular telephone having an external connector that is

formed into the housing of the telephone so as to form a tight, water resistant seal between the

external connector and the housing structure of the telephone. In one embodiment, the

external connector is inserted into the lower edge of the telephone housing structure. In

particular the external connector includes a series of contacts that are individually insert

molded into the housing structure. In a second embodiment, during the process of molding

the housing, a series of apertures are formed in the housing structure of the cellular telephone

and thereafter the individual contacts that comprise the external connector are press fitted into the formed apertures in such a fashion that a generally tight and water resistant seal is formed

between the individual contacts and the apertures formed within the housing structure.

In both embodiments discussed above, the individual contacts that form the external

connector are designed to form a pressure connection with a printed circuit board connector or

to contacts that are formed on the printed circuit board. Thus the connection between the

external connector and the printed circuit board is a nonpermanent pressure type connection

that is created by the selective positioning of the printed circuit board within the housing

structure of the cellular telephone.

It is therefore an object of the present invention to provide a cellular telephone with an

external connector that is formed or incorporated within the housing structure of the cellular

telephone such that a generally tight and water resistant seal is effectively formed between the

individual contacts that comprise the external connector and the housing structure of the

cellular telephone.

Another object of the present invention is to provide a cellular telephone with an

external connector of the character described above wherein the external connector makes

contact with the printed circuit board through a nonpermanent pressure connection.

Other objects and advantages of the present invention will become apparent and

obvious from a study of the following description and the accompanying drawings, which are

merely illustrative of such invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a perspective view of the cellular telephone of the present invention. Figure 2 is a fragmentary perspective view of the cellular telephone, illustrating an

insert-molded connector formed in the housing structure of the cellular telephone. Figure 3 is

a fragmentary perspective view of the cellular telephone illustrating a second embodiment

where the external connector is press fitted into a series of molded apertures formed in the

housing structure of the cellular telephone.

Figure 4 is a fragmentary exploded view of the cellular telephone of the present

invention illustrating a third embodiment for the external connector wherein a grill or

cosmetic cover is adapted to be disposed adjacent the outer side of the external connector.

Figure 5 is a fragmentary perspective view of the third embodiment illustrating the

cosmetic cover or grill and the printed circuit board disposed in their normal position within

the cellular telephone.

DETAILED DESCRIPTION OF THE INVENTION

Shown in Fig. 1 is a cellular telephone, generally indicated by the numeral 10.

Cellular telephone 10 includes an enclosure or housing, which is comprised of an upper

section 12 and a lower section 14 adapted so as to couple together and effectively form a case

or shell around the components contained within. As shown in Fig. 1, the upper section 12 of

the housing contains a number of significant functional elements. For example, disposed

about the exterior face of the upper housing 12 is a display panel 16, which allows the internal

circuitry of the phone to effectively communicate with the user in a visual manner. Adjacent

the display panel 16 is an earphone or speaker 18, which facilitates audio communication.

Also disposed on the face of the upper housing 12 is a keypad 20, which provides the user

with a tactile data entry or input interface. A microphone 22 is located adjacent the keypad 20 and is disposed so as to accept audio input from the user. Immediately adjacent the display

panel 16, at one end of the upper housing 12, is an antenna 24, while the other end of the

upper housing 12 includes an external electrical connector, which is generally indicated by the

numeral 50. A battery pack 30 is provided and adapted to be mounted to the backside of the

lower housing section 14.

The above description generally describes the cellular telephone 10 as particularly

shown in Figure 1. Details of the cellular telephone 10 are not dealt with herein in detail

because such is not per se material to the present invention, and because basic cellular

telephone technology is well known and understood by those skilled in the art. Further,

cellular telephones of the general type shown in Figure 1 and discussed above are

commercially available and are manufactured by various manufacturers, including Ericsson,

Inc., of Research Triangle Park, North Carolina, 27709.

Disposed within the cellular telephone 10 is a printed circuit board 26. Printed circuit

board 26 is adapted to be electrically coupled to the external connector 50. As will be

appreciated from subsequent portions of the disclosure, the connection between the printed

circuit board 26 and the external connector 50 will be a nonpermanent pressure connection.

Accordingly, in the embodiments shown in Figures 2 and 3, the printed circuit board 26 is

provided about one edge portion with a series of discreet electrically conductive contact pads

28. In order to appropriately locate the printed circuit board 26 and the contact pads 28 for

connection with the external connector 50, the housing structure of the cellular telephone 10

is, in conventional fashion, provided with one or more circuit board locators (not shown) that automatically position the printed circuit board 26 in a proper position within the cellular

telephone 10.

Shown in Fig. 2 is a first embodiment of the external connector 50 of the present

invention. In this first embodiment, the connector 50 is generally comprised of a series of

electrically conductive contacts 52 which are embedded or formed into the wall of the upper

housing 12 through an insert molding process. That is, during the housing fabrication process

the individual contacts 52 are temporarily supported within the mold while liquid plastic resin

is injected or poured in and generally around them. Once this plastic housing material has

solidified or hardened, the individual contacts 52 are permanently set within the wall of the

upper housing 12, and furthermore, the interface established between the contacts 52 and the

adjacent plastic housing is so tight as to effectively form a seal which is generally waterproof

and impermeable to moisture. Consequently, the overall connector 50 exhibits a generally

waterproof or water-resistant property or characteristic. That is, as a consequence of the

molding process, a sealed relationship is established between the contacts 52 and the adjacent

plastic housing 12, such that moisture or other debris from the external environment is not

permitted to pass freely into the interior cavity of the phone 10.

With particular regard to the contacts 52 illustrated in Fig. 2, it will be appreciated that

these contacts are comprised of a relatively thin strip of an electrically conductive material

such as copper or the like, and that this relatively thin conductive strip of material is bent or

formed into a generally V-shaped configuration. As such, each contact 52 includes an

elongated external contacting face 54, an angled spring arm 56, and an internal contact or

contacting tab 58. As a consequence of the insert molding process described above, each contact 52 is oriented within the side wall of the upper housing 12 such that the elongated

external contacting face 54 is positioned vertically and generally exposed for connection to a

corresponding external electrical contact (not shown). The angled spring arm 56 extends

generally inwardly from the upper edge of the external contacting face 54. Formed about the

lower edge of the angled spring arm 56 is the L-shaped internal contacting tab 58. The V-

shaped bent configuration provides the contact 52 with a generally resilient or spring-like

property. More particularly, when the telephone internals are assembled and the printed

circuit board 26 is properly positioned adjacent the series of contacts 52, the free portion of

each angled spring arm 56 is elastically deformed as the internal contacting tabs 58 are

forcibly pressed against the contact pads 28 which are formed on the exposed surface of the

printed circuit board 26. The resilient nature of the contacts 52 causes the displaced angled

spring arm 56 to exert a reaction force which causes the associated internal contacting tabs 58

to generally remain in contact with the adjacent printed circuit board 26, and more particularly

to remain in contact with the electrical contact pads 28 disposed on the board 26, as shown in

Fig.2.

In this manner, the external connector 50 provides a series of electrically conductive

pathways from designated areas on the printed circuit board 26 to the external contact faces

54. More particularly, these electrically conductive pathways, which essentially penetrate the

protective upper housing 12, are disposed within the housing wall via an insert molding or

similar process such that a generally sealed, moisture resistant barrier is formed between the

individual contacts 52 and the surrounding housing. With respect to the V-shaped spring type contacts 52 described and discussed above, it

will be appreciated by those skilled in the art that there are any number of specific contact

shapes or configurations that may be successfully employed in the cellular telephone 10. In

the end, such contacts should lend themselves to insert molding or permanent incorporation

into the telephone housing structure, provide externally exposed surfaces for interfacing with

external electrical connections, and provide internal contacts which establish and maintain a

reliable electrical connection with the internal printed circuit board 26.

In the embodiment shown in Fig. 2, external connector 50 assumes the form of a series

of individual contacts with each individual contact being insert molded into the housing

structure of the cellular telephone. However, it is contemplated that the individual contacts

could first be molded into a carrier plate to form a contact assembly, and thereafter, that the

entire contact assembly could be insert molded or press fitted into the housing of the cellular

telephone. Either way, the net effect is to provide a generally waterproof seal between the

contacts and the housing structure, or between the contact assembly and the housing structure.

It will therefore be appreciated that the external connector 50 can be used as an

interface for connecting the cellular telephone 10 to a wide variety of electrical connections.

For example, the sealed external connector 50 of the present invention can be employed to

make an external power connection with a battery charger or a general data communications

connection. Additionally, in order to receive certain external connection devices, the housing

of the cellular telephone 10 in the area occupied by the external connector 50 can be provided

with conventional attachment means (not shown) for receiving the external connection device and maintaining an electrical connection between the external connection device and the

external connector 50 formed within the housing of the cellular telephone.

Shown in Fig. 3 is a second embodiment of the present invention. As in the first

embodiment, the external connector 50 is generally comprised of a series of electrically

conductive, V-shaped contacts 52. However, in the case of the second embodiment, these

contacts are not directly insert molded within the wall of the upper housing 12. Instead, a

series of openings or appetures 32 are formed in the wall of the upper housing 12 during the

molding process. These openings or appetures 32 are sized so as to precisely accommodate

the V-shaped contacts 52 which are inserted during a fabrication step which follows the initial

molding of the housing structure The contacts are typically inserted into the housing appetures

32 and secured therein by press fitting.

As shown in Fig. 3, the appetures 32 that are formed in the housing wall during the

initial molding process are sized so as to accommodate the contacts 52 in the same basic

orientation as described for the first embodiment. That is, each press fitted contact 52 is

oriented within the side wall of the upper housing 12 such that the elongated external

contacting face 54 is positioned vertically and generally exposed for connection to a

corresponding external electrical connector (not shown). As a consequence of the press fit

insertion process, the exposed surfaces of the elongated external contact surfaces 54 are

wedged into the appetures 32 in such a manner so as to generally secure the contacts 52

therein. That is, the four edges of each external contact surface 54 are generally wedged

tightly between the four walls of the appeture 32. As a consequence of this tight interface that

is formed between the press fitted contact 52 and walls of the appeture 32, a seal or barrier is effectively established which acts to prevent moisture or other external debris from passing

through and into the interior cavity of the telephone 10. As with the first embodiment, the

angled spring arms 56 extend inwardly from the upper edge of the external contacting faces

54. Formed on the lower edge of the angled spring arms 56 are the L-shaped internal

contacting tabs 58.

Once again, the V-shaped bent configuration provides the contact 52 with a generally

resilient or spring-like property. More particularly, when the telephone internals are

assembled and the printed circuit board 26 is properly positioned adjacent the series of

contacts 52, each angled spring arm 56 is elastically deformed as the internal contacting tabs

58 are forcibly pressed against the contact pads 28 which are formed on the exposed surface

of the printed circuit board 26. The resilient nature of the contacts 52 causes the displaced

angled spring arms 56 to exert a reaction force which causes the associated internal contacting

tabs 58 to generally remain in contact with the adjacent printed circuit board 26, and more

particularly to remain in contact with the electrical contact pads 28 disposed on the board 26,

as shown in Fig.3.

Turning to Figures 4 and 5, another embodiment of the present invention is disclosed

therein. Here the external connector 50 is in the form of a series of contact slugs 70 that are

insert molded or press fitted into a recessed wall 72 that forms a part of the upper housing 12

of the cellular telephone 10. Note that the respective contact slugs 70 include outer terminal

ends that project outwardly from the recessed wall 70 and inner terminal ends that project

inwardly from the same recessed wall 70. It is appreciated that the outer terminal ends form

the contacting surfaces that actually engage and make electrical contact with an external device such as a battery charger or receiving cr^'adle. Likewise the inner terminal ends of the

contact slugs 70 are adapted to form a pressure connection with the printed circuit board 26 or

in this case a printed circuit board connector 74 that is attached to the end of printed circuit

board that is normally disposed adjacent the contact slugs 70.

Formed in the front housing 12 adjacent the recessed wall 72 is a molded seat that

includes a bottom ledge 76 and a pair of opposed side edges 78. Each side edge 78 includes

an elongated vertical groove 80 formed therein. Mounted in the seat is a grill or cosmetic

cover, indicated generally by the numeral 82. Cosmetic cover 82 includes a surrounding

frame 84 and a series of grill slats 88 that project generally vertically between the upper and

lower members of the surrounding frame 84. Disposed on opposite sides of the frame 84 is a

pair of tongues 86 that are adapted to project into and slide through the vertical grooves 80.

It is contemplated that in one embodiment, the backside of the cosmetic cover 82

could be provided with a series of open grooves (not shown) that are particularly spaced for

receiving the outer terminal ends of the contact slugs 70 that project outwardly from the

recessed wall 72. That is, when the cosmetic cover 82 assumes the installed position shown in

Figure 5, the outer terminal ends of the contact slugs 70 would project into and at least

partially through the grooves formed on the backside of the cosmetic cover 82. The outer end

portions of the contact slugs 70 would still be accessible through the slats 88 formed in the

cosmetic cover 82. This would effectively isolate and control the pitch between respective

contacts and further this arrangement would provide structural support and help ensure that

the contacts do not deform. In addition, and alternatively, a gasket rhaterial such as silicone or epoxy could be

disposed between the cosmetic cover and the molded geometry of the seat area defined for

receiving the cosmetic cover. This would provide additional environmental protection for the

internal areas within the cellular telephone should the seal between the housing and the

contact slugs break as a result of the cellular telephone being dropped.

In the case of the embodiment shown in Figures 4 and 5, it is appreciated that the

connection between the contact slugs 70 and the contacts 74a that form a part of the printed

circuit board connector 74 is a nonpermanent pressure contact. More particularly, it will be

appreciated that once the printed circuit board 26 is appropriately located internally within the

housing structure of the cellular telephone 10, the contacts 74a carried on the printed circuit

board connector 74 will align with the inner end portions of the contact slugs 70. Because of

the arrangement of the contact slugs 70 and the position occupied by the printed circuit board

connector 74, and due to the spring nature of the contacts 74a, a continuous pressure type

connection is maintained between the contact slugs 70 and the respective contacts 74a.

In the embodiment illustrated herein, the external connector 50 is connected to the

printed circuit board in various ways. One approach not expressly shown, entails the use of a

conductive elastomer. Basically the conductive elastomer would be interposed but electrically

connected between the external connector 50 and appropriate contacts on the printed circuit

board. Because of the elastic nature of the conductive elastomer it follows that the conductive

elastomer would compensate for tolerances and yet maintain a continuous electrical

connection between the external connector 50 and the printed circuit board. From the foregoing specification and discussion, it is seen that the cellular telephone

of the present invention includes an external connector 50 that is insert molded or press fitted

into the housing of the cellular telephone so as to create or form a generally water resistant

seal between the external connector and the housing structure. This protects the internal

environment within the housing of the telephone and prevents moisture, dust, and other debris

from passing between the external connector and the housing structure into the internal areas

of the cellular telephone.

The present invention may, of course, be carried out in other specific ways than those

herein set forth without departing from the spirit and essential characteristics of the invention.

The present embodiments are, therefore, to be considered in all respects as illustrative and not

restrictive, and all changes coming within the meaning and equivalency range of the appended

Claims are intended to be embraced therein.

Claims

CLAIMSWhat Is Claimed Is:

1. A cellular telephone having an insert molded external connector formed in the

housing of the telephone, comprising:

a) a housing structure;

b) a printed circuit board disposed within the housing structure;

c) an external connector insert molded in the housing structure such that a

sealed relationship is formed between the housing structure and the

external connector; and

d) the external connector having one or more externally exposed contact

surfaces, and one or more internal contact surfaces that operatively

connect the external connector with the printed circuit board.

2. The cellular telephone of claim 1 wherein in the internal contact surfaces

project inwardly from the housing and engage contacts associated with the printed circuit

board through a pressure connection.

3. The cellular telephone of claim 1 wherein the external connector includes a

series of individual contacts and wherein the individual contacts are each independently

insert molded into the housing structure such that a sealed relationship is formed between

each individual contact and the surrounding housing structure.

4. The cellular telephone of claim 3 wherein each insert molded contact includes

an external contact surface, and an internal contact surface that projects inwardly from the housing structure for engagement with at least one contact point associated with the printed

circuit board.

5. The cellular telephone of claim 4 wherein the internal contact surfaces are

spring biased for engagement with the contact points associated with the printed circuit

board.

6. The cellular telephone of claim 3 wherein each contact includes a contact

surface that is disposed generally within the plane of the housing structure, and a spring

finger extending inwardly from the contact surface.

7. The cellular telephone of claim 6 wherein the spring finger includes a terminal

contact pad for engaging a contact associated with the printed circuit board.

8. The cellular telephone of claim 1 including a grill secured within the housing

and disposed adjacent an outer side of the external connector.

9. The cellular telephone of claim 1 wherein the seal formed between the insert

molded external connector and the housing structure is waterproof.

10. A cellular telephone having an integral and sealed external connector

incorporated within the housing thereof, comprising:

a) a housing structure;

b) a printed circuit board disposed within the housing structure;

c) a series of molded apertures formed in the housing structure;

d) an external connector having a series of contacts press fitted into the

respective molded apertures to form a tight sealed relationship between

the housing structure and the contacts; and e) each contact having an externally exposed surface, and an internal

surface that operatively connects to the printed circuit board.

11. The cellular telephone of claim 10 wherein each individual contact includes a

spring finger that projects inwardly from the external surface towards the printed circuit

board.

12. The cellular telephone of claim 1 1 wherein each respective spring finger

includes a terminal end portion that includes the internal surface that operatively connects the

respective contacts to the printed circuit board.

13. The cellular telephone of claim 11 wherein a nonpermanent pressure

connection is formed between the respective individual contacts and the printed circuit board.

14. A cellular telephone having an external connector permanently mounted within

a portion of a housing structure forming a part of the cellular telephone, comprising:

a) a housing structure;

b) a printed circuit board disposed within the housing structure and having

at least one contact associated therewith;

c) an external connector permanently mounted and secured within the

housing structure;

d) wherein there is formed a water resistant seal between the external

connector and the molded aperture; and

e) the external connector having at least one externally facing contact

surface and at least one internal contact surface that makes a

nonpermanent pressure contact with the contact associated with the printed circuit board.

15. The cellular telephone of claim 14 wherein the external connector is

permanently mounted within the housing structure through an insert molding process.

16. The cellular telephone of claim 14 wherein the external connector is press

fitted into a molded aperture formed in the housing after the housing itself has been molded.

17. The cellular telephone of claim 15 wherein the external connector includes a

series of individual contacts with each contact being insert molded into the housing structure

such that a water resistant seal is formed between each individual contact and the housing

structure.

18. The cellular telephone of claim 16 wherein the external connector includes a

series of individual contacts and wherein each individual contact is press fitted into a separate

molded aperture formed in the housing structure so as to form a water resistant seal between

each individual contact and the housing structure.

19. The cellular telephone of claim 14 wherein the internal contact surface forms a

part of a spring finger that biases the internal contact surface into engagement with the contact

associated with the printed circuit board such that once the cellular telephone is assembled

there is continuous electrical contact between the external connector and the printed circuit

board.