GB2327908A

GB2327908A - Keypad membrane having integrated elastomeric connectors

Info

Publication number: GB2327908A
Application number: GB9716606A
Authority: GB
Inventors: Werner Zuber
Original assignee: Motorola GmbH
Current assignee: Motorola Solutions Germany GmbH
Priority date: 1997-08-02
Filing date: 1997-08-02
Publication date: 1999-02-10
Also published as: GB9716606D0

Abstract

A keypad membrane 58 having elastomeric connectors 60 integrated during manufacture, wherein the connector has electrically conductive regions for coupling a first circuit element (e.g. a circuit board 56) to a second circuit element (e.g. a button 58). A keypad arrangement with integrated connectors is formed by inserting the connectors into a moulding element and then over-moulding the connectors with the membrane.

Description

KEYPAD ARRANGEMENT AND METHOD OF MANLJFACTURE THEWEOF 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, and its role in the formation of a radio control head is shown in the perspective view of FIG. 1. The radio control head 34 includes a number of orifices 22. The radio control head 34 slots on top of a moulded body of a keypad 36, which once moulded includes a number of keypads 28 for protruding through, in use, the respective orifices 32. In between the radio control head 34 and the moulded keypad 36 a number of individual parts are positioned to be respectively connected during manufacture.

The individual parts include a liquid crystal display (LCD) 24, an LCD gasket 23, an LCD frame 25 and elastomeric connectors 30. The radio control head 34, once attached to the moulded keypad via the individual part is connected to a printed circuit board 26 such that the elastomeric connectors 30 form an electrical contact with corresponding positions on the printed circuit board 26. Electrical contacts on the display 24, correspond to the elastomeric connectors to form an electrical contact with the printed circuit board 26 through the respective elastomeric connectors 30. In a manufacturing process, the handling, stocking and coupling of these parts is costly.

This invention seeks to alleviate some of the aforementioned problems associated with current keypad arrangements, and in particular, to provide a more efficient, inexpensive and quicker method for manufacturing keypad arrangements, particularly for 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 keypad membrane, a first and second circuit element and at least one elastomeric connector containing electrically conductive regions for electrically coupling the first electrical component to the second electrical component in use. The at least one elastomeric connector is integrated into the keypad membrane during manufacture.

In this manner, the manufacture of the keypad arrangement is simplified, the keypad arrangement is more durable, reliable and less costly than other keypad arrangements requiring more parts.

In the preferred embodiment of the invention, the at least one elastomeric connector is made of a flexible material and the keypad membrane includes a sealing region to fixedly attach and ease the insertion of the keypad arrangement into a receptacle unit, such as a radio control head.

Preferably, the first circuit element is a printed circuit board and the second circuit element is at least one of the following: a display, a speaker, a light emitting diode, a microphone, an antenna, a switch, a button.

According to a second aspect of the present invention a method for manufacturing a keypad arrangement is provided. The method includes the steps of inserting at least one electrically contactable element into the moulding element; and injecting a keypad membrane into the moulding element to form a keypad arrangement with an integrated at least one electrically contactable element. Preferably the at least one electrically contactable element is an elastomeric connector.

In an alternative embodiment of the invention the electrically contactable element is at least one of the following: a display, a speaker, a light emitting diode, a microphone, an antenna, a switch, a button.

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 FIG. 1 is a perspective view showing the steps in manufacturing a prior art keypad arrangement; FIG. 2 is a perspective view showing the steps in manufacturing a keypad arrangement according to the preferred embodiment of the invention.

FIG. 3 shows a side view of the manufactured keypad arrangement according to the preferred embodiment of the invention.

Detailed Description of the Drawings Referring to FIG. 2, a perspective view showing the steps in manufacturing a keypad arrangement according to a preferred embodiment of the invention is shown. The keypad arrangement 48 includes a radio control head 64 having a number of orifices 62. The radio control head 64 is connected to a moulded keypad 66, containing a number of respective user interface elements (buttons) 58 that insert into, when built, the respective orifices 62. The moulded keypad 66 further includes elastomeric connectors 60 and an LCD frame that have been moulded into the keypa,d during manufacture and a sealing area. The moulded keypad 66 is positioned on a printed circuit board 56 such that the elastomeric connectors 60 form an electrical contact with corresponding positions on the printed circuit board 56.

In the preferred embodiment of the invention, a one piece display 54, is inserted in a snap-fit manner into the moulded keypad 66. Electrical contacts on the display 54, correspond to the elastomeric connectors to form an electrical contact with the printed circuit board 56 through the respective elastomeric connectors 60.

It is within the contemplation of the invention that a number of alternative methods of moulding the elastomeric connectors into the keypad can be used. A first manufacturing method for moulding the keypad includes over-moulding the elastomeric connectors 60 with the keypad, ensuring that the electrically contactable sections of the elastomeric connectors 60 are free from the keypad mould. An alternative manufacturing method for moulding the keypad includes fixing the elastomeric connectors 60 into close fitting receptacles, or applying a glue to fix the elastomeric connectors 60 in the keypad, and applying the mould around the elastomeric connectors 60.

Referring to FIG. 3, a side view of the manufactured keypad arrangement according to the preferred embodiment of the invention is shown. The keypad arrangement 48 includes a radio control head 64 having a number of user interface elements (buttons) 62 inserted through orifices on the housing. The radio control head 64 slots on top of a moulded keypad 66, and includes the moulded user interface elements (buttons) 62.

In the preferred embodiment of the invention a display 54, is inserted in a snap-fit manner into the moulded keypad 66. Electrical contacts on the display 54, correspond to the elastomeric connectors to form an electrical contact with the printed circuit board 56 through the respective elastomeric connectors 60. In this manner, bessels, separate sealing parts and connectors, as used in prior art keypad arrangements, are no longer required. The elastomeric connectors are made of silicon rubber parts to allow some compression of the connector when positioned between the display 54 and the printed circuit board 56. The sealing area 52 is also made of a flexible material such as rubber, so as to form a protective seal when the display 54 is inserted into the moulded keypad 66.

In this fashion, the sealing area will prevent undesirable elements, such as dust and water,.entering the radio.

Furthermore, there is no need for a frame to hold the connectors and display in position. The keypad is preferably extended to cover the whole front side of the housing to form a total seal to the front side thereby providing additional protection to the gasket below the speaker.

In addition, it is within the contemplation of the invention that alternative designs to achieve such an integrated arrangement of the keypad can be used and that the inserted electrical element may be at least one of the following: a display, a speaker, a light emitting diode, a microphone, an antenna, a switch, a button.

Thus a keypad arrangement and method of manufacture are provided that alleviates some problems associated with known technology.

Claims

1. A keypad arrangement comprising: a first and second circuit element; and a keypad membrane having at least one elastomeric connector containing electrically conductive regions for electrically coupling the first circuit element to the second circuit element in use, wherein the at least one elastomeric connector is integrated into the keypad membrane during manufacture of the keypad membrane.

2. A keypad arrangement according to claim 1, wherein the at least one elastomeric connector is made of a flexible material to ease the insertion of the keypad arrangement into a receptacle unit.

3. A keypad arrangement according to claim 1 or 2 wherein the keypad membrane includes a sealing region to fixedly attach the keypad arrangement into the receptacle unit.

4. A keypad arrangement according to any one of claims 1, 2 or 3, wherein the first circuit element is a printed circuit board and the second circuit element is a button.

5. A method of manufacturing a keypad arrangement having a main body the method comprising the steps of: inserting at least one electrically contactable element into the moulding element; and injecting a keypad membrane into the moulding element to form a keypad arrangement with an integrated at least one electrically contactable element.

6. A method of manufacturing a keypad arrangement in accordance with claim 5, wherein the step of inserting at least one electrically contactable element into the moulding element further includes at least one of the following: fixing the at least one electrically contactable element into at least one close fitting receptacle, applying a fixing compound into the moulding element for fixedly receiving the at least one electrically contactable element.

7. A method of manufacturing a keypad arrangement in accordance with claims 5 or 6, wherein the at least one electrically contactable element is an elastomeric connector.

8. A method of manufacturing a keypad arrangement in accordance with claims 5 or 6, wherein the electrically contactable element is at least one of the following: a display, a speaker element, a light emitting diode, a microphone, a switch.

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

10. A keypad arrangement substantially as hereinbefore described with reference to, or as illustrated by, FIG. 3 of the drawings.