Side key connection device of mobile terminal

A side key connection device of a mobile terminal simplifies a connection structure between a side key and a main circuit board. The mobile terminal includes a side key and a row and column terminal pad. The mobile terminal also includes a side key connection device installed between the side key and the row and column terminal pad. The side key connection device is electrically connected to the side key and the row and column terminal pad. Thereby, by simplifying a connection structure of a side key, a key cost, an assembly process, and a surface mounting cost can be reduced.

The present application is related to and claims the benefit under 35 U.S.C. §119(a) of a Korean Patent Application filed in the Korean Intellectual Property Office on Nov. 20, 2009 and assigned Serial No. 10-2009-0112512, the entire disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a side key connection device of a mobile terminal, and more particularly, to a side key connection device of a mobile terminal that simplifies a side key connection structure.

BACKGROUND OF THE INVENTION

In general, a side key of a mobile terminal is installed in at least one side of a main body of the mobile terminal. The side key is a key for enabling the mobile terminal to send a signal through manipulation and to execute a desired function.

Typically, side keys of mobile terminals can be classified as either a dome switch type or a tact switch type.

The dome switch type side key attaches a dome sheet that includes a dome switch therein to a flexible printed circuit board (FPCB) and solders the FPCB to a connection terminal, i.e. a row and column terminal pad formed in a main circuit board. For the dome switch, a rubber dome switch or a metal dome switch is used.

The tact switch type side key solders and connects a tact switch element to a row and column terminal pad formed in a main circuit board.

Typically, the tact switch uses surface mount devices (SMD) to which surface mount technology (SMT) is applied.

However, when the dome switch is used, an FPCB for attaching a dome sheet is manufactured, and the FPCB is soldered to the main circuit board. In order to fix the FPCB, a fixing support is provided at a side surface of the main circuit board and is fixed by a double-sided tape.

When the tact switch is used, the tact switch is surface mounted to the main circuit board to correspond to the quantity of the side keys.

For such dome switch type side keys, a FPCB is expensive, the dome switch type side key includes many assembly processes, and the main circuit board occupies much space for the FPCB. For tact switch type side keys, a tact switch and surface mounting are expensive, and the main circuit board may increase the thickness of the mobile terminal by a thickness of the tact switch.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, it is a primary object to provide a side key connection device of a mobile terminal that can simplify a side key structure in order to provide a side key function without using a dome switch or a tact switch.

The present invention further provides a side key connection device of a mobile terminal that can reduce a key cost, an assembly process, and a surface mounting cost.

The present invention further provides a side key connection device of a mobile terminal that can easily reduce a thickness by increasing mounting space.

In accordance with an aspect of the present invention, a mobile terminal includes a side key and a row and column terminal pad. The mobile terminal also includes a side key connection device installed between the side key and the row and column terminal pad and configured to be electrically connected to the side key and the row and column terminal pad.

In certain embodiments, the side key connection device may includes a side row and column terminal pad extended from the row and column terminal pad to a side surface of a main circuit board to be integrally formed. The side key connection device may also include a conductive connection member housed in a housing groove formed in the side key in order to electrically connect the side row and column terminal pad. The side key connection device may further include a pair of elastic members, each having one end coupled to an end of a side surface of the side key opposite to the side surface of the main circuit board and having the other end coupled to the side surface of the main circuit board in order to elastically move the side key.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 through 7, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged mobile terminal. Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention.

FIG. 1is a perspective view illustrating a mobile terminal according to an embodiment of the present invention.FIG. 2is an exploded perspective view of the mobile terminal ofFIG. 1.FIG. 3is a cross-sectional view of the mobile terminal taken along line A-A′ ofFIG. 1.FIG. 4illustrates a state before operating a side key of the mobile terminal ofFIG. 1.FIG. 5illustrates a state after operating a side key of the mobile terminal ofFIG. 1.

Referring toFIGS. 1-3, a mobile terminal100can be formed as a fold type terminal or a slide type terminal. For convenience of description, it is assumed that the mobile terminal100is a slide type terminal.

The mobile terminal100includes a main circuit board10, main body20, slide unit30, side key50, and side key connection device70.

The side key connection device70includes a side row and column terminal pad71, conductive connection member73, and a pair of elastic members75.

The side key connection device70is installed between the main circuit board10and the side key50. The side key connection device70, the main circuit board10, and the side key50are installed within the main body20. The main body20is divided into an upper case21and a lower case23.

The side row and column terminal pad71is extended from a row and column terminal pad13(to be described later) to a side surface of the main circuit board10. The side row and column terminal pad71is integrally formed. That is, the side row and column terminal pad71is an electrically connected extension pad and, in certain embodiments, is formed by deposition.

The deposition may include a physical vapor deposition (PVD) or a chemical vapor deposition (CVD). PVD and CVD are well known technology and therefore a detailed description thereof is omitted.

A plurality of row and column terminal pads13are formed in at least one of an upper surface and a lower surface of the main circuit board10. The row and column terminal pads13are separated from each other, and are electrically connected to a side key driving circuit12. Each row and column terminal pad13is soldered and coupled to a connection terminal of an existing tact switch (not shown) or side key FPCB (not shown). Therefore, in the present embodiment, an existing complicated side key structure is simplified by the side key connection device70connected to the side key50(to be described later) using the row and column terminal pad13.

The side key driving circuit12outputs an input signal of the side key50to a central processing unit (CPU), and is formed at one side of an upper surface of the main circuit board10. The side key driving circuit12is formed in the main circuit board10together with the electrically connected row and column terminal pad13. The row and column terminal pad13includes a key value in a row and column unit. Therefore, when the side key50is pressed, a signal input corresponding to a key value is output to the CPU by the side key driving circuit12.

In the present embodiment, only one row and column terminal pad13is formed, however the quantity of row and column terminal pads13is not limited thereto. For example, a plurality of row and column terminal pads13may be provided on both sides of an upper surface of the main circuit board10.

The side key50includes a side key button50athat can be manipulated when a user presses the button50awith a hand, and a blade50bintegrally formed with a circumferential surface of a lower end of the side key button50a. In the side key50, a pair of case grooves25are formed opposite to side surfaces of the upper case21and the lower case23. Side portions of the side key button50aare coupled and thus some of a front portion of the side key button50ais protruded. The blade50bis fixed by latching to a pair of latch jaws27formed behind the side key groove25such that the side key50is not exposed to the outside.

In the present embodiment, one side key50is formed, however the quantity of side keys50is not limited thereto. For example, a side key50can be installed in both sides of the mobile terminal to correspond to the quantity of the row and column terminal pad13.

The conductive connection member73is formed in a shape that includes a volume and is housed within and fixed to a housing groove50cformed in a rear surface of the side key50opposite to the side row and column terminal pad71. This arrangement enables the side row and column terminal pad71to electrically connect by contacting with the side row and column terminal pad71. In this case, it is preferable that some of the conductive connection member73is housed in the housing groove50cto make contact with the side row and column terminal pad71and the remaining portions of the conductive connection member73are exposed. The conductive connection member73can be made of a conductive material such as gold, silver, copper, and iron. In the present embodiment, the conductive connection member73is inserted into the side key50. However, in certain embodiments, the conductive connection member73may be formed in a plate shape to be bonded with adhesives or be formed using conductive pigment or conductive spray.

Therefore, when the conductive connection member73of the side key50simultaneously contacts with the side row and column terminal pad71by pressing the side key button50a, the side key driving circuit12is electrically connected.

In order to elastically move the side key50, one end of each of a pair of elastic members75is coupled to an end of a rear surface of the blade50bof the side key50opposite a side surface of the main circuit board10. The other end of each elastic member75elastically contacts a side surface of the main circuit board10. The blade50bof the side key50and the pair of elastic members75are coupled and fixed between both ends of a rear surface of the blade50bof the side key50and the ends of the pair of elastic members75using a pair of double-sided tapes60. The other ends of the pair of elastic members75opposite to a side surface of the main circuit board10elastically contact a side surface of the main circuit board10. However, the ends of the elastic members75may be fixed using a pair of double-sided tapes60. In the present embodiment, a pair of double-sided tapes60are used, however it is not limited to the pair of double-sided tapes60. For example, the other ends of the pair of elastic members75can be fixed using adhesives.

In order to sustain a state where the side key50is pressed to the outside, a pair of elastic members75contact with a side surface of the main circuit board10in a state where the pair of elastic members75are compressed to some degree. In an embodiment, each elastic member75may be a Z-shaped flat spring or a compression spring. Further, in the present embodiment, the pair of elastic members75are flat springs, however they are not limited thereto. For example, coil springs may be used.

In the present embodiment, the side key connection device70is applied to the main body20in which the main circuit board10and the side key50are installed. However, the embodiment is not limited thereto. For example, the side key connection device70can be applied to the slide unit30that includes a display unit33therein.

In order to install the side key connection device70, the side key50and the main circuit board10can be provided.

A vibration can be operated to notify that the conductive connection member73simultaneously contacts with the side row and column terminal pad71. The vibration can be operated to interlock with a vibration device installed within the mobile terminal100. That is, the input of a signal of the side key50can be notified by a vibration.

Further, a lamp can be operated to notify that the conductive connection member73simultaneously contacts with the side row and column terminal pad71. The lamp can operate to interlock with the side key50or a light emitting apparatus of the keypads28and35positioned at a front portion of the main body20and the slide unit30. That is, the input of a signal of the side key50can be notified by turning on a lamp. The lamp may be a light emitted diode (LED).

In addition to the above-described elements, the mobile terminal100may include other elements included in a typical mobile terminal such as a battery, touch pad, camera module, and slide hinge module. These are well known elements and therefore a detailed description thereof is omitted.

Next, operation of the side key50is described with reference toFIGS. 4 and 5.

Referring toFIG. 4, when an external force is not applied to the side key50, the conductive connection member73and the side row and column terminal pad71are separated from each other by the pair of elastic members75. In this case, a signal input of the side key50is interrupted. When a front portion of a side key button50aexposed from the main body20is pressed, the pair of elastic members75are compressed, and the conductive connection member73inserted into a rear surface of the side key50simultaneously contacts with the row and column terminal pad71of the side surface, as shown inFIG. 5. That is, an input signal of the side key50is input to the side key driving circuit12. In this case, the input of the key signal can be determined by a vibration or a lamp.

When the side key button50ais released, the pair of compressed elastic members75are restored, and the side key button50ais returned to an original position, as shown inFIG. 4. Thereby, a contact between the conductive connection member73and the row and column terminal pad71of the side surface is separated, and an input signal of the side key50is interrupted.

FIG. 6is a perspective view illustrating a coupling structure of a side key of a mobile terminal according to another embodiment of the present invention.FIG. 7is a cross-sectional view illustrating a coupling structure of the side key of the mobile terminal ofFIG. 6.

Referring toFIGS. 6 and 7, in the present embodiment, a side key connection device70includes a side row and column terminal pad71, a conductive connection member73, and a pair of elastic members75.

The present embodiment includes the same configuration as that of the previous embodiment, except that a pair of key grooves50dand protrusions15are formed in the side key50and the main circuit board10, respectively, of the previous embodiment. Therefore, a detailed description thereof is omitted.

Specifically, in order to rigidly couple the side key50, the main circuit board10, and a pair of elastic members75together, a pair of key grooves50dthat can be coupled to one end of the pair of elastic members75are formed at both ends of the side key50.

In a side surface of the main circuit board10opposite to the side key50, a pair of protrusions15are provided that can be coupled to the other end of each of the pair of elastic members75. The pair of protrusions15may be integrally formed with the main circuit board10or attached to the main circuit board10. Insertion grooves15athat can be coupled to the other ends of the pair of elastic members75are formed at opposite sides of the pair of protrusions15.

In this way, by inserting both ends of a pair of elastic members75into a pair of key grooves50dof the side key50and a pair of insertion grooves15aof the main circuit board10, respectively, the pair of elastic members75can be rigidly and stably fixed.

As described above, according to the present invention, by simplifying a connection structure of a side key, a key cost, an assembly process, and a surface mounting cost can be reduced.

Further, mounting space for other components of a main circuit board can be increased, and an entire thickness of the mobile terminal can be easily reduced.