Flip-cover sensor for keypad

There is disclosed a keypad apparatus and a method for determining the status of a keypad apparatus. In one embodiment, the keypad apparatus includes a keypad having a plurality of keys and a keypad matrix associated with the keypad and having a switch. The keypad apparatus also includes a cover moveable between an open and a closed position. The keypad apparatus still further includes a means for engaging that cooperates with and allows the switch to provide a status indicating a position of the cover.

CROSS-REFERENCE TO FOREIGN APPLICATION

This application claims the benefit of EP Patent Application No. 02251790.8 entitled “Flip-Cover Sensor for Keypad,” to David J. Bennetts, et al., filed on Mar. 13, 2002, which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention is directed, in general, to a keypad apparatus having a keypad housing with a flip-cover and, more specifically, to a mobile telephone or a personal digit assistant (PDA) having a flip-cover.

BACKGROUND OF THE INVENTION

While there may be a general desire to minimize the size of mobile telephones, there is a physical restriction in reducing the size due to a need for the ear piece to be positioned proximate the user's ear at the same time as the mouth piece is positioned proximate the user's mouth. This theoretically dictates that the length of the mobile telephone must be a certain minimum size.

It has been recognized that the position of the ear piece and the mouth piece is only critical when the mobile telephone is in use. Based on this, mobile telephones have been developed with a ‘flip-cover.’ When the mobile telephone is not in use, the flip-cover folds or slides back onto a keypad housing of the mobile telephone and, therefore, does not increase the overall size of the mobile telephone. When a call is to be made or received, the flip-cover is opened such that the length of the mobile telephone becomes longer and the mouthpiece for the user is more practically positioned.

Typically, mobile telephone designs having a flip-cover include a means such that the state of the flip-cover, either open or closed, is detected. The detection of the flip-cover state, for example, may be used for answering a call (on opening the flip-cover) and terminating a call (on closing the flip-cover).

Presently, a sensor switch, such as a micro-switch, may be recessed within the surface of the keypad housing to engage with a switch activator on the cover. The switch activator is usually a small protrusion that extends into a recess of a surface of the mobile telephone when the flip-cover is closed thereby engaging, or activating, the sensor switch. This sensor switch provides an input signal to a general-purpose input/output (GPIO) pin of a micro-controller within the mobile telephone. Thus, the micro-controller within the mobile telephone receives a dedicated signal indicating whether the flip-cover is open or closed.

One disadvantage with this present detection of the flip-cover state is that the provision of extra pins on the micro-controller integrated circuit package increases the cost of the integrated circuit. Therefore, the provision of a dedicated GPIO pin to the micro-controller for the purpose of detecting the status of the flip-cover increases the cost of the micro-controller integrated circuit. Alternatively, using a spare GPIO pin for this purpose prevents it from being used for another purpose.

One proposal for detecting the flip-cover state includes using a switch matrix associated with a keypad of the mobile telephone. A switch of the switch matrix may receive a signal which in an alternate detection process would have been provided to the GPIO pin of the micro-controller. In such a proposal, when the particular switch of the matrix is not pressed, a signal is sent to a keypad controller to indicate that the flip cover is open. The disadvantage with this proposal, however, is that an entire row of the keypad switch matrix is inoperable while the flip cover is open since one of the switches in that row of the switch matrix will be constantly activated. Hence that row is not usable. The proposal, therefore, is not practical since it is unlikely that an entire row of the switch matrix may be unused and still provide a sufficient number of keys for normal operation of the mobile telephone.

Accordingly, what is needed in the art is an improved arrangement for detecting the status of a flip-cover associated with a keypad apparatus, such as a mobile phone, that overcomes the deficiencies in the prior art.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, the present invention provides a keypad apparatus. In one embodiment, the keypad apparatus (e.g., a mobile phone) includes a keypad having a plurality of keys and a keypad matrix associated with the keypad and having a switch. The keypad apparatus also includes a cover moveable between an open and a closed position. The keypad apparatus still further includes a means for engaging that cooperates with and allows the switch to provide a status indicating a position of the cover. When the cover is in the closed position, the status of the switch corresponds to a key pressed state.

In a preferred embodiment, the means for engaging may include a switch actuator. The switch actuator may be a protrusion on the surface of the cover that engages the switch when the cover is in the closed position. The switch may be recessed in a housing of the keypad.

In another embodiment, at least one of the plurality of keys is preferably uncovered with the cover in the closed position. In yet another embodiment, with the cover in the open position, the status of the switch preferably corresponds to a key unpressed state.

According to the present invention, there is also provided a method for determining the status of a keypad apparatus. In one embodiment, providing a keypad having a plurality of keys and a keypad matrix associated with the keypad and having a switch. The method also includes allowing a cover to move between an open and a closed position and selectively engaging the switch to provide a status indicating a position of the cover. When the cover is in the closed position, the status indicates that the keypad apparatus is in a key pressed state.

The method preferably includes covering at least one of the plurality of keys with the cover in the closed position. The method also preferably includes uncovering at least one of the plurality of keys with the cover in the open position. With the cover in the open position, the status of the switch preferably corresponds to a key unpressed state.

DESCRIPTION OF PREFERRED EMBODIMENT

The present invention is described herein with reference to a particular non-limiting example. A person skilled in the art will appreciate that the invention is more generally applicable. In particular, the present invention is described in relation to a mobile telephone. However, the present invention may be more broadly applied to any keypad apparatus and, particularly, to a housing in which a keypad is situated.

Referring initially toFIG. 1, there is illustrated a mobile telephone, generally designated10, in which the invention may be advantageously utilized. The mobile telephone10includes a main housing14and a cover12. The main housing14includes a screen20, and a top surface of the housing30within which is provided a plurality of keys26collectively forming a keypad. The cover12is attached to the main housing14by means of a hinge24at the junction of the top surface of the housing30and a side surface of the housing28. The cover12is movable with respect to the main housing14by means of the hinge24, such that in a closed position the cover12rests on a portion of the main housing14. In an open position, the cover12extends beyond the main housing14, such that in the illustrated embodiment the top surface of the housing30upon which the keypad is provided is uncovered. In moving from the closed to open position, the cover12moves through approximately 180 degrees. The cover12may be a typical flip-cover that is well-known in the art.

As can be seen fromFIG. 1, the top surface of the housing30may include an opening16. Referring toFIG. 2, which shows a cross-section through A—A ofFIG. 1, the opening16is shown to extend into the main housing14.FIG. 2also illustrates that the cover12includes a protrusion18which extends from the surface thereof. The protrusion18is shaped such that it engages the opening16. Thus with the cover12closed, the protrusion18extends into the opening16.

As shown inFIG. 2, in the main housing14there is provided a switch17. The protrusion18is adapted such that with the cover12closed, the protrusion18engages the switch17to switch or change a state of the switch17. Thus, if the switch17is normally open, the protrusion18closes the switch17on closing the cover12. If the switch17is normally closed, the protrusion18opens the switch17on closing the cover12. The main housing14, therefore, is provided with a means to engage to indicate the status of the cover12by cooperatively engaging with the cover12.

In accordance with the present invention, the switch17comprises a switch of a keypad matrix array, and provides an input signal to a handset micro-controller of the mobile telephone10in a similar manner as the plurality of keys26ofFIG. 1may provide an input signal. This is further discussed with reference to FIG.1.

Referring toFIG. 3, there is illustrated an embodiment of a matrix arrangement, generally designated33, for processing inputs provided by the plurality of keys26. The matrix arrangement33will be familiar to one skilled in the art, and only the necessary details are discussed herein to understand the prevent invention.

The matrix arrangement33is a 5×5 matrix, which allows for 25 keys to be connected thereto. The matrix arrangement33comprises a set of 25 switches34a-42e. Each switch is associated with a key. Pressing a key activates the associated switch. The switches34a-42eare arranged in five rows34,36,38,40,42. Each row has five columns a, b, c, d, e. Each of the switches34a-42eprovides an input on a column line to a matrix controller32, which may be, for example, a micro-controller of the mobile telephone10. The switches34a-34eprovide an input to the matrix controller32on line44, the switches36a-36eprovide an input to the matrix controller32on line46, the switches38a-38eprovide an input to the matrix controller32on line48, the switches40a-40eprovide an input to the matrix controller32on line50, and the switches42a-42eprovide an input to the matrix controller32on line52. The matrix controller32generates an output to the switches in row a on line54, to the switches in row b on line56, to the switches in row c on line58, to the switches in row d on line60, and to the switches in row e on line62.

As is known in the art, responsive to depression of one of the plurality of keys26, the associated switch of the matrix arrangement33is closed. For the purposes of an illustrative example, assume that the switch38cis closed. Responsive thereto, a signal is generated on line48to the matrix controller32. In order to determine which of the switches in the row38has generated such a signal, the matrix controller32sequentially applies a signal on column lines54,56,58,60,62and at the same time continues to monitor row line48. As the switch38cis closed, the matrix controller32sees a change in the signal on line48when a signal is applied to line58, and the matrix controller32thereby identifies which switch has been closed. One skilled in the art will understand the operation of the matrix arrangement33.

In a typical application, the matrix arrangement33may have redundant switches. That is, the matrix arrangement33may have more switches than are needed to provide for the plurality of keys26of the mobile telephone10. Spare matrix switches, therefore, may be available. For example, the mobile telephone10may have a total of 22 keys resulting in three redundant or spare switches in the matrix arrangement33. One skilled in the art will understand that in view of the matrix arrangement33, the spare switches may be provided even though they are redundant.

In accordance with the preferred embodiment of the present invention, one of the spare switches of the matrix arrangement33may be utilized as the switch17ofFIG. 2for detecting the status of the cover12. For example, assuming switches42c,42d,42eare spare switches, then the switch42emay be allocated for use as the switch17of FIG.2. When the switch42eis closed (or opened depending on the configuration of the switches), the closing of the cover12is detected directly by the matrix controller32using conventional inputs and outputs as shown in FIG.3. Similarly the opening of the cover12from a closed position may also be detected. Thus the matrix controller32does not require any additional input/output pins in order to detect the status of the cover12.

InFIGS. 1 and 2, the cover12covers all of the plurality of keys26while in other embodiments this may not be the case. The cover12, for example, may cover a selected number of the plurality of keys26(e.g., the volume keys may be uncovered). The cover12may also cover none of the plurality of keys26since the purpose of the cover12may be to reduce the overall size of the mobile telephone10when not receiving or making a telephone call. For example, there may be a desired application where the cover12does not cover any of the plurality of keys26when a user enters numbers into memory of the mobile telephone10which does not require setting up an active call. In these instances, the location of the opening16will be positioned appropriately in order to ensure appropriate engagement with the cover12on closing.

Turning now toFIG. 4, illustrated is a block diagram of an embodiment of a mapping of external inputs of the mobile telephone10.FIG. 4illustrates some of the plurality of keys26mapped to various switches of the matrix arrangement33of FIG.3. In addition,FIG. 4illustrates the protrusion18mapped to the switch42eof the matrix arrangement33.

According toFIG. 4, the mobile telephone10may operate as follows. When the cover12is open, then the switch42eis not engaged by the protrusion18and the switch42eis an “unpressed key” from the perspective of the matrix controller32. When the cover12is closed, then the switch42eis engaged by the protrusion18and the switch42eis a “pressed key” from the perspective of the matrix controller32.

The status of the cover12, therefore, may be incorporated as part of the matrix arrangement33. The ‘open’ status of the cover12may be determined by a “key unpressed” state whereas the ‘closed’ status of the cover10may be determined by a “key pressed” state. The “key pressed” state means that the row of the switch matrix is unusable. However, this does not matter if all the keys of that row are covered by the closed cover12or if any other switches of the matrix arrangement33associated with that row are unused. The number and identifications of the plurality of keys26covered on detection of closure of the cover12may be determined by the matrix controller32of the mobile telephone10and may depend upon a physical design of the mobile telephone10.

Although the invention has been described herein with reference to a mobile telephone having a ‘flip’ cover, the applicability of the present invention is not so limited. The invention may apply equally advantageously, for example, in a keypad apparatus having a keypad with a slide cover. The opening and closing of the slide cover may be detected in the same way as described above regarding the cover12of the mobile telephone10. The present invention, therefore, broadly applies to any device having a keypad with a moveable cover.

Further, inputs to a matrix array of switches to determine the status of a cover may be implemented by alternative means. For example, in an alternative implementation of the present invention, the protrusion18on the cover12may engage with an actual dedicated key of the plurality of keys26rather than the opening16. In such an alternative implementation, there would preferably need to be a spare key available on the keypad for such use.

The invention has been described herein with reference to particular preferred embodiments. One skilled in the art will appreciate the broader applicability of the present invention, the scope of which is limited only by the attached claims.