GB2324414A

GB2324414A - Keypad arrangement

Info

Publication number: GB2324414A
Application number: GB9707547A
Authority: GB
Inventors: Hans-Juergen Schmidt
Original assignee: Motorola GmbH
Current assignee: Motorola Solutions Germany GmbH
Priority date: 1997-04-15
Filing date: 1997-04-15
Publication date: 1998-10-21
Anticipated expiration: 2017-04-15
Also published as: GB9707547D0; GB2324414B

Abstract

A keypad arrangement (30) includes a printed circuit (40) and a keypad for electrically coupling to the printed circuit (40). The keypad includes at least first (36) and second electrical contacts (37). The keypad is deployable from a stowed position to a deployed position and the first contact (36) is electrically coupled to a first portion of the printed circuit (40) in the stowed position. In a deployed position the first electrical contact (36) is electrically uncoupled from the first portion of the printed circuit (40) and the second electrical contact (37) is electrically coupled to a second portion of the printed circuit (40). Thus the keypad arrangement (30), when depressed, breaks a first electrical contact and momentarily forms a second electrical contact.

Description

KEYPAD ARRANGEMENT AND METHOD OF OPERATION TEIEBEFOR Field of the Invention This invention relates, in general, to keypad arrangements and is particularly, but not exclusively, applicable to keypad arrangements for use in radio communication units.

Background of the Invention A keypad allows a user to either enter information into, or select functions from, electronic equipment. In the case of portable radio units, a large number of different features can be offered, with the user-choice of those features being controlled by, and in some cases limited by, the number of buttons keys on the keypad.

An example of a standard keypad, is shown in FIG. 1. The keypad 10 includes a number of buttons 12, often termed keys. Each button 12 is attached to each of its adjacent neighbour buttons, by a number of angular abutments 18 and the whole structure encased within a housing 14, typically manufactured from rigid material. A conductive tip 16 is deposited at the bottom tip of each button 12 to contact with a particular track or contact point on a printed circuit board 20. A number of cavities are provided within the housing 14 so as to allow movement of each button 12 and thereby access of each conductive tip 16 to the printed circuit board 20.

In an equilibrium position for the keypad, the conductive tip 16 of each button 12 rests marginally above the printed circuit board 20. Upon depression of a button 12 an electrical circuit, comprising the conductive tip 16 and the printed circuit board 20, is completed, thereby activating a selected function of the unit associated with the respective depressed button 12. Upon release of the key 12, a spring effect of the angular abutment 18, restores the key to its equilibrium position.

In communication units the multiple feature and function requirement results in a number of keypad arrangements being used with the same radio housing to offer different features, for example a numbered keypad to dial a desired radio unit for basic units may have some blank keys for use in higher tier models to initiate say, emergency calling.

Furthermore, an alphanumeric keypad could be used to offer the additional feature of data transmissions. Specifically, each keypad may be labelled with several different instructions which uniquely relate to particular functions or operating mode, but will have the same mechanical parameters. Hence, the use of a keypad is limited to the function whereby a single depression of a key initiates the selection of a specific function.

For a range of electronic equipment, and in particular radio products, the requirement of larger keypads to offer ever more features, creates additional cost to the radio unit and requires a comparable increase in space.

This invention seeks to alleviate some problems with current keypad arrangements, and in particular, to provide a more efficient arrangement for selecting features and functions in electronic equipment such as mobile and portable communication units.

Summary of the Invention According to a first aspect of the present invention a keypad arrangement is provided. The keypad arrangement includes a receptacle unit and an engaging unit for electrically coupling to the receptacle unit, wherein activation of the engaging unit provides a breakable electrical contact with the receptacle unit. In this manner, activation of the engaging unit serves to disconnect the receptacle unit from an electrical contact.

In the preferred embodiment of the invention, the engaging unit having at least first and second electrical coupling means. The engaging unit is deployable from a stowed position to a deployed position and the first electrical coupling means is electrically coupled to a first portion of the receptacle unit in the stowed position and in a deployed position the first electrical coupling means is electrically uncoupled from the first portion of the receptacle unit and the second electrical coupling means is electrically coupled to a second portion of the receptacle unit.

Preferably, the receptacle unit is a printed circuit board and the engaging unit is a keypad such that coupling of the first electrical coupling means to the first portion of the printed circuit board activates a first function of the keypad arrangement. When a respective key of the keypad is depressed the first function is disconnected from its electrical coupling and a second function is activated in response to the second electrical coupling means being electrically coupled to the second portion of the printed circuit board. In the preferred embodiment of the invention, the keypad arrangement further includes a substantially rounded fulcrum positioned substantially between the first electrical coupling means and second electrical coupling means, such that depression and release of the respective key rotates the electrical contact around the fulcrum and switches the keypad arrangement between operating in the first function mode of operation and the second function mode of operation.

In this manner, the keypad arrangement, when depressed, breaks a first electrical contact and momentarily forms a second electrical contact.

Advantageously, a simple mechanical element is used to determine which, of at least two, electrical contacts are formed in a keypad, with at least one contact formed when the key is not depressed.

According to a second aspect of the present invention a method for switching between electrical contacts in a keypad arrangement is provided. The method includes the steps of attaching a keypad to a printed circuit board such that a first electrical contact is formed between at least one key of the keypad and the printed circuit board and depressing a button on the keypad causing the first electrical contact to disconnect and a second electrical contact to form.

In the preferred embodiment of the invention, the keypad arrangement has a keypad with at least two electrically contactable positions for electrically contacting with distinct portions of a printed circuit board. A first electrical contact of the at least two electrical contacts is created with a breakable contact and the second electrical contact of the at least two electrical contacts is created with a momentary contact.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the drawings.

Brief Description of the Drawings Brief Description of the Drawings FIG. 1 shows a prior art keypad arrangement; and FIG. 2 shows a keypad arrangement according to the preferred embodiment of the invention.

Detailed Description of the Drawings Referring to FIG. 2, a keypad arrangement according to the preferred embodiment of the invention is shown. The keypad arrangement 30 includes a number of buttons 32. Each button 32 is attached to each of its adjacent neighbour buttons, by a number of angular abutments 38 and the whole structure encased within a housing 34, typically manufactured from rigid material. First and second conductive tips 36 and 37 are deposited at the bottom tip of at least one button 32 to contact with particular tracks or contact points on a printed circuit board 40. First and second conductive tips 36, 37 are separated by a rounded protrusion 42, in contact with the printed circuit board 40. A number of cavities are provided within the housing 34 so as to allow movement of each button 32 and thereby access of each conductive tip 36, 37 to the printed circuit board 40.

In an equilibrium position for the keypad, the first conductive tip 36 of at least one button 32 rests on the printed circuit board 40, such that an electrical connection is made between first conductive tip 36 and an associated track/ contact point on the printed circuit board 40. Upon depression of the respective button 32, the rounded protrusion 42 rotates its contact point with the printed circuit board 40 and causes a breaking of the contact of the first conductive tip 36 and the printed circuit board 40.

Furthermore, the rotational movement of the rounded protrusion 42 causes the second conductive tip 37 to form an electrical contact between itself and an associated track/ contact point on the printed circuit board 40.

Upon release of the button 32, a spring effect of the angular abutments 38, restores the button to its equilibrium position, thereby breaking the electrical contact of conductive tip 37 and forming an electrical contact between conductive tip 36 and its associated track/ contact point on the printed circuit board 40.

Furthermore, it is within the contemplation of the invention that alternative designs to achieve such a mechanical dual-contact coded keypads of various configurations. One such alternative arrangement could include say a "T" shape keypad to facilitate a three-way electrical connection.

Thus an electrically coupled equipment, namely a keypad arrangement, and method of operation are provided that alleviates some problems associated with known technology.

Claims

1. A keypad arrangement comprising: a receptacle unit; and an engaging unit for electrically coupling to the receptacle unit, wherein activation of the engaging unit provides a breakable electrical contact with the receptacle unit.

2. A keypad arrangement according to claim 1 wherein the engaging unit has at least first and second electrical coupling means, the engaging unit being deployable from a stowed position to a deployed position and the at least first electrical coupling means is electrically coupled to a first portion of the receptacle unit in the stowed position and when in a deployed position the first electrical coupling means is electrically uncoupled from the first portion of the receptacle unit and the second electrical coupling means is electrically coupled to a second portion of the receptacle unit.

3. A keypad arrangement according to claim 1 or 2 wherein the receptacle unit is a printed circuit, the engaging unit is a keypad such that coupling of the at least first electrical coupling means to the first portion of the printed circuit board activates a first function of the keypad arrangement and when a respective key of the keypad is depressed the first function is disconnected from its electrical coupling and a second function is activated in response to the at least second electrical coupling means being electrically coupled to the second portion of the printed circuit board.

4. A keypad arrangement according to any one of the preceding claims, further comprising a fulcrum positioned substantially between the first electrical coupling means and second electrical coupling means, such that depression and release of the respective key switches the keypad arrangement between operating in the first function mode and the second function mode.

5. A keypad arrangement according to claim 4 wherein the fulcrum is substantially rounded in shape to facilitate switching the keypad arrangement between operating in a first function mode of operation and the second function mode of operation.

6. A keypad arrangement according to any one of the preceding claims wherein the keypad arrangement is housed in a radio communications unit.

7. A method for switching between electrical contacts in a keypad arrangement, the method comprising the steps of: attaching a keypad to a printed circuit board such that a first electrical contact is formed between at least one key of the keypad and the printed circuit board; and depressing a button on the keypad causing the first electrical contact to disconnect and a second electrical contact to form.

8. A method for switching between electrical contacts in a keypad arrangement according to claim 7, the keypad arrangement having a keypad with at least two electrically contactable positions for electrically contacting with distinct portions of a printed circuit board, wherein a first electrical contact of the at least two electrical contacts is created with a breakable contact and the second electrical contact of the at least two electrical contacts is created with a momentary contact.

9. A keypad arrangement substantially as hereinbefore described with reference to, or as illustrated by FIG. 2 of the drawings.