WO2020162863A1

WO2020162863A1 - Touch pad assemblies for electronic devices

Info

Publication number: WO2020162863A1
Application number: PCT/US2019/016453
Authority: WO
Inventors: Chun Hsien Wang; Chien-Ting Lin; Cheng-Chieh Chen
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2019-02-04
Filing date: 2019-02-04
Publication date: 2020-08-13
Also published as: TW202036256A; TWI731568B

Abstract

A touch pad assembly for an electronic device is described. The touch pad assembly comprises a switch for electrically connecting a first contact with a second contact, a moveable touch pad, a base 5 plate, and a resiliently deformable element that is connected to an underside of the touch pad and is retained by a protrusion on a base plate. The switch is operable by the moveable touch pad. A cushioning material comprising a polymer is disposed between the underside of the touch pad and the protrusion. The polymer is selected from a silicone, a 10 polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof.

Description

TOUCH PAD ASSEMBLIES FOR ELECTRONIC DEVICES

BACKGROUND

[0001] Electronic devices, such as keyboards for computers and laptops, often include a touch pad. The touch pad allows a user to operate an electronic device in a similar way to a mouse. By passing a finger over the touch pad, a user can move a cursor shown on the display screen of the electronic device. Some touch pads incorporate a button or a switch as part of the touch pad, which allows the user to click or select an object shown on the display screen.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Figure 1 is a simplified cross-section through an example of a touch pad assembly of the present disclosure.

[0003] Figures 2 and 3 each show an exploded view of an example of a touch pad assembly of the present disclosure.

[0004] Figure 4 is a simplified cross-section through an example of a touch pad assembly of the present disclosure.

[0005] The figures depict several examples of the present disclosure. It should be understood that the present disclosure is not limited to the examples depicted in the figures.

DETAILED DESCRIPTION

[0006] As used in the present disclosure, the term“about” is used to provide flexibility to an endpoint of a numerical range. The degree of flexibility of this term can be dictated by the particular variable and is determined based on the associated description herein.

[0007] Amounts and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not just the numerical values explicitly recited as the limits of the range, but also to include individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. [0008] As used in the present disclosure, the term“comprises” has an open meaning, which allows other, unspecified features to be present. This term embraces, but is not limited to, the semi-closed term“consisting essentially of and the closed term“consisting of. Unless the context indicates otherwise, the term “comprises" may be replaced with either“consisting essentially of or“consists of.

[0009] It is noted that, as used in this specification and the appended claims, the singular forms“a”,“an” and“the” include plural referents unless the context clearly dictates otherwise.

[0010] As used in the present disclosure, the terms“conductive” or“insulative” refers to a feature that is electrically conductive or electrically insulative

respectively.

[0011] As used in the present disclosure, the term“contact” used in the context of a switch, such as the“first contact” or the“second contact”, is synonymous with the term“terminal”.

[0012] The present disclosure refers to the terms“first cushioning material” and “second cushioning material”. The reference to“first” in the term“first cushioning material” is used as a label to distinguish the associated cushioning material from the feature represented by the term“second cushioning material”. The reference to“second” in the term“second cushioning material” is also a label. The use of “first” and“second” in these terms is not intended to restrict the number of cushioning materials that are present. Thus, a reference to only the“second cushioning material” does not require the presence of two cushioning materials, namely a“first cushioning material” and a“second cushioning material".

[0013] The term“elastomer” as used herein refers to a polymer having elastic properties. The elastomer may be a natural polymer or a synthetic polymer. In an example, the elastomer is a synthetic polymer. The elastomer may not comprise rubber.

[0014] The present disclosure refers herein to a touch pad assembly for an electronic device and to an electronic device.

[0015] The touch pad assembly for an electronic device comprises a switch for electrically connecting a first contact with a second contact, a moveable touch pad, a base plate, and a resiliently deformable element that is connected to an underside of the touch pad and is retained by a protrusion on a base plate. The switch is operable by the moveable touch pad. A cushioning material comprising a polymer is disposed between the underside of the touch pad and the protrusion. The polymer is selected from a silicone, a polyurethane, a polyester, a

polypropylene, an elastomer and a combination of two or more thereof.

[0016] In an example, the cushioning material may comprise polyurethane.

[0017] The resiliently deformable element may, in one example, be a

compression spring. The compression spring may be a dome shaped metal spring.

[0018] In an example, the cushioning material may be disposed on the resiliently deformable element.

[0019] In another example, the cushioning material may be disposed on an underside of the touch pad and within the resiliently deformable element.

[0020] The cushioning material described above may be a first cushioning material and may be disposed on an underside of the touch pad and within the resiliently deformable element. A second cushioning material may be disposed on the resiliently deformable element. The second cushioning material may comprise a polymer selected from a silicone, a polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof. In one example, the second cushioning material comprises a polyurethane.

[0021] The touch pad may comprise a touch pad surface and a printed circuit board (PCB) on an underside of the touch pad surface.

[0022] The first contact of the switch may be on the PCB.

[0023] The second contact of the switch may be on the PCB.

[0024] The switch may be arranged to form an electrical connection between the first contact and the second contact when the resiliently deformable element is compressed, such as by operation of the moveable touch pad.

[0025] The resiliently deformable element may be metallic and arranged to form an electric connection between the first contact and the second contact when compressed.

[0026] In use, the impact between an underside of the touch pad and the compression of the resiliently deformable on the protrusion can generate a noise. Without the presence of a cushioning material, this noise may resonate within the resiliently deformable element and the space between the touch pad and the base plate. This noise can be irritating for the user or may disturb other nearby users, especially when the touch pad is pressed repeatedly.

[0027] The present disclosure can, for example, provide a noiseless touch pad assembly. The cushioning material may also reduce the mechanical wear of the components within the touch pad assembly.

[0028] The electronic device comprises a housing containing an electrical circuit; and a touch pad assembly within the housing.

[0029] It is to be understood that this disclosure is not limited to the housings, electronic devices or methods disclosed herein. It is also to be understood that the terminology used in this disclosure is used for describing particular examples.

Touch pad assembly

[0030] The touch pad assembly of the present disclosure comprises a switch.

The switch is for electrically connecting a first contact with a second contact. The switch opens and closes an electrical circuit.

[0031] The switch is operable by a moveable touch pad. The touch pad is vertically moveable in relation to the base plate. The touch pad is moveable in the sense that it can be pushed or pressed like a button to actuate the switch. The touch pad provides an actuator for the switch.

[0032] The touch pad may, for example, be operable by a user to select an object shown on a display screen. When the touch pad is pressed, the switch is actuated and an electrical connection is formed between the first contact and the second contact.

[0033] The switch may be a tact switch, such as a PCB tact switch.

[0034] The touch pad may comprise a touch pad surface. The touch pad surface is for accepting a touch operation, such as a touch operation performed by a user. The touch pad surface may, for example, allow a user to control a cursor shown on the display screen of an electronic device. This can be achieved when a user touches and passes a finger over the touch pad surface in, for example, the direction of intended travel of the cursor. [0035] The touch pad surface may comprise an insulative material.

[0036] The touch pad surface may comprise glass or plastic.

[0037] The touch pad surface may be provided by a touch pad plate, such as a glass or a plastic plate.

[0038] The touch pad may comprise a printed circuit board (PCB) The PCB may be on an underside of the touch pad surface, such as an underside of the touch pad plate.

[0039] The PCB comprises a touch sensor for detecting a touch operation by a user. The touch sensor may be a pressure sensitive sensor, a capacitive sensor, an optical sensor or a surface acoustic wave sensor.

[0040] A resiliently deformable element is connected to an underside of the touch pad. The connection between the resiliently deformable element and the underside of the touch pad may be a mechanical connection. The purpose of the resiliently deformable element is to restore the touch pad to its original position after it has been pressed.

[0041] The switch may comprise the resiliently deformable element. In a first position of the touch pad, the resiliently deformable element may be arranged to electrically disconnect the first contact from the second contact. In a second position of the touch pad, the resiliently deformable element may be arranged to electrically connect the first contact with the second contact, such as when the resiliently deformable element is compressed.

[0042] When the resiliently deformable element is connected to an underside of the touch pad, then the resiliently deformable element may, for example, be connected to the PCB. In one example, the resiliently deformable element is mechanically connected to the PCB. The resiliently deformable element may be directly mechanically connected to the PCB. Thus, the resiliently deformable element is in contact with the PCB.

[0043] The resiliently deformable element may have a first end and a second end. The first end of the resiliently deformable may be connected to the underside of the touch pad. The first end of the resiliently deformable element may be directly mechanically connected to the PCB. [0044] The resiliently deformable element may be attached to the PCB or the resiliently deformable element may be retained by the PCB. The first end of the resiliently deformable element may be attached to or retained by the PCB.

[0045] The resiliently deformable element may be elastic. When the resiliently deformable element is elastic, it is elastically deformed when it is compressed.

[0046] The resiliently deformable element may be a spring, such as a

compression spring. The compression spring may be a dome shaped spring, a cylindrical shaped spring, a conical spring or a helical spring. In one example, the compression spring is a dome shaped spring.

[0047] The resiliently deformable element may be conductive. The resiliently deformable element may comprise a conductive metal. When the resiliently deformable element is made of a conductive metal, then it may form part of the electrical connection between the first contact and the second contact.

[0048] When the resiliently deformable element is conductive, then it may be a metallic spring, such as a metallic compression spring. In one example, the resiliently deformable element is a dome shaped metal spring.

[0049] When the resiliently deformable element is a conical spring or a helical spring, then the second end of the resiliently deformable element is one end of the spring and the first end of the resiliently deformable element is the opposite end of the spring. For a conical spring, the second end of the resiliently deformable element may be the end of the spring having the smaller diameter, such as the end nearer to the apex of the cone.

[0050] When the resiliently deformable element is a dome shaped spring, then the second end of the resiliently deformable element is provided by the curved surface of the dome, such as the peak of the dome. The first end of the resiliently deformable element may be provided by the circular edge at the base of the dome.

[0051] When the resiliently deformable element has a dome shape, a peak portion of the dome shape may be disposed directly on the protrusion of the base plate.

[0052] When the resiliently deformable element is a cylindrical shaped spring, then the second end of the resiliently deformable element is provided by a circular face of the cylinder. This end of the cylinder may be closed. [0053] The first end of the resilient!y deformable element may be provided by the circular edge at the base of the cylinder. This end of the cylinder may be open.

[0054] The touch pad assembly comprises a base plate. The base plate is disposed under the touch pad. The base plate may form part of a support structure for the touch pad. The base plate may be fixable to a housing of the electronic device, such as by passing a screw through the base plate into the housing.

[0055] The base plate may have a cavity. The cavity may provide an area for housing a component of the touch pad or the electronic device. Electrical circuitry or an electrical contact, such as a wire or terminal, may pass through the cavity to, for example, connect the touch pad to a circuit board.

[0056] The cavity may provide space for movement of the switch.

[0057] In general, the base plate has a protrusion. The protrusion is on a surface of the base plate. The protrusion may be an integral part of the base plate.

[0058] The protrusion may project toward an underside of the touch pad. The protrusion may, for example, be cylindrical or hemispherical shaped.

[0059] The resiliently deformable element is retained by the protrusion on the base plate. In general, the resiliently deformable element is retained between the touch pad and the protrusion.

[0060] The second end of the resiliently deformable element may be retained by the protrusion. Thus, the second end of the resiliently deformable element may rest on the protrusion or press against the protrusion.

[0061] In a first position, no pressure is applied to the touch pad. Thus, the touch pad has not been pressed or pushed.

[0062] When pressure is applied to the touch pad, such as by pressing or pushing the touch pad, the resiliently deformable element is compressed between the protrusion and the touch pad. The first end of the resiliently deformable element is pushed toward the protrusion. The protrusion can retain the second end of the resiliently deformable element in the same position, such that applying pressure to the touch pad decreases the distance between the first end and the second end, thereby compressing the resiliently deformable element. [0063] The protrusion may, for example, control the direction of deformation of the resiliently deformable element in use, such as when it is compressed. Thus, the protrusion may direct all or part of the resiliently deformable element toward the PCB. This directed part of the resiliently deformable element may, for example, be used to electrically connect the first contact with the second contact.

[0064] The touch pad has a second position where pressure has been applied to it, such as by pressing or pushing. In the second position, the movement of the touch pad may be restricted, such that it will not move by applying further pressure. This is to prevent the touch pad from being pressed or pushed further.

In the second position, the touch pad has been fully pressed or pushed.

[0065] Applying pressure to the touch pad electrically connects the first contact with the second contact of the switch. Thus, the switch is closed when, for example, the touch pad is pressed.

[0066] Releasing the pressure applied to the touch pad, for example, when a user stops pressing or pushing the touch pad, allows the resiliently deformable element to decompress, thereby restoring the touch pad to its first position.

[0067] When the resiliently deformable element is compressed, the second end of the resiliently deformable element may be brought into contact with an underside of the touch pad, such as the PCB.

[0068] The impact between (t) the underside of the touch pad or the PCB and (ii) the second end of the resiliently deformable retained by the protrusion can generate a noise. This noise may resonate within the resiliently deformable element and the space between the touch pad and the base plate. This noise can be irritating for the user or may disturb other nearby users, especially when the touch pad is pressed repeatedly. This interaction may also result in mechanical wear of the components of the touch pad assembly, such as the resiliently deformable element or the PCB. This wear may reduce their lifetime and the components can be costly for a user to replace.

[0069] The present disclosure can provide a noiseless touch pad assembly. The lifetime of the components in the touch pad assembly may also be extended. [0070] The touch pad assembly comprises a cushioning material. When the switch comprises the resiliently deformable element, then the switch may comprise the cushioning material.

[0071] The cushioning material is disposed between the underside of the touch pad and the protrusion. The cushioning material may be disposed between the PCB and the protrusion.

[0072] In one example, the cushioning material is disposed between the PCB and the second end of the resiliently deformable element.

[0073] The cushioning material may be disposed on the PCB or on the resiliently deformable element. A cushioning material may be disposed on the PCB and a separate cushioning material may be disposed on the resiliently deformable element.

[0074] When the cushioning material is disposed on the PCB, then the

cushioning material may be disposed within the resiliently deformable element, such as within the first end of the resiliently deformable element.

[0075] When the cushioning is disposed on the resiliently deformable element, then cushioning material may be disposed within the resiliently deformable element, such as at the second end of the resiliently deformable element.

[0076] In use, the cushioning material is positioned between the protrusion of the base plate and the touch pad or parts thereof. The cushioning material can absorb energy from the mechanical impact between the protrusion and the touch pad or its parts, thereby preventing noise and mechanical wear of the switch.

[0077] In general, the cushioning material is disposed as a layer. The layer may have a thickness of about 5 mm to about 1 mm, such as about 10 mm to about 500 mm or about 50 mm to about 250 mm. The layer of the cushioning material should have a thickness that does not impede the motion of the touch pad or the resiliently deformable layer.

[0078] In general, the cushioning material comprises a polymer, which may be selected from a silicone, a polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof.

[0079] In one example, the cushioning material is a silicone. In a further example, the cushioning material is a polyester. In another example, the cushioning materia! is a polypropylene. In a further example, the cushioning material is an elastomer.

[0080] The cushioning material, in an example, comprises a polyurethane.

[0081] The type of cushioning material that is used may affect the mechanical properties of the touch pad assembly. The cushioning materials above may be more robust and lighter than, for example, natural rubber. They may also have superior energy absorbing properties, which may prevent further mechanical wear of the components of the touch pad assembly and the production of a noise when the touch pad is pressed. When the cushioning material is a polyurethane, then the touch pad assembly may possess such beneficial properties.

[0082] The polymer of the cushioning material may have a weight average molecular weight of about 10,000 to about 800,000, such as about 25,000 to about 500,000 or about 50,000 to about 250,000. The weight average molecular weight of the polymer may affect its elasticity and its ability to absorb an impact.

[0083] In general, the polymer may comprise an additive.

[0084] The additive may be a polymer stabilizer, such as processability

improvement additive, a durability improvement additive, an antioxidant, or weatherability improvement additive. The processability improvement additive may be selected from a phosphorus type additive, a phenol type additive, a calcium type additive, a zinc type additive and a barium type additive. The durability improvement additive may be selected from a phenol type additive and a thioether type additive. The antioxidant may be selected from a hydrazide type additive and an amide type additive. The weatherability improvement additive may be selected from an ultraviolet absorber and a hindered amine light stabilizer. The ultraviolet absorber may be a benzotriazole type additive or a triazine type additive.

[0085] The additive may be functionalizing additive. The functionalizing additive may be selected from a plasticizer, a flame retardant and an antistatic property enhancement additive. The plasticizer may be a phthalic acid type additive or an epoxy type additive. The flame retardant may be a phosphorus type additive. The antistatic property enhancement additive may be a nonionic type additive, an anionic type additive or a cationic type additive. [0086] The polymer may comprise the additive in an amount from about 0.5 wt% to about 20 wt%, such as from about 1.0 wt% to about 15 wt%, from about

1.5 wt% to about 10 wt%. In one example, the polymer comprises the additive in an amount of less than 5.0 wt%.

[0087] When a cushioning material is disposed on the PCB, then this cushioning material may be referred to herein as the“first cushioning material”.

[0088] The first cushioning material may be disposed on a surface of the PCB. The first cushioning material may be a layer disposed on the surface of the PCB.

[0089] The first cushioning material may be disposed above the protrusion of the base plate.

[0090] The layer of the first cushioning material may be a circular. This circular layer may fit within the first end of the resiliently deformable element.

[0091] The layer may have a thickness of about 5 mm to about 1 mm, such as about 10 mm to about 500 mm or about 50 mm to about 250 mm.

[0092] The first cushioning material comprises a polymer, which may be selected from a silicone, a polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof.

[0093] In one example, the first cushioning material is a silicone. In a further example, the first cushioning material is a polyester. In another example, the first cushioning material is a polypropylene. In a further example, the first cushioning material is an elastomer.

[0094] The first cushioning material may, for example, comprise a polyurethane. When the first cushioning material is a polyurethane, then the touch pad assembly may have a silent operation.

[0095] The polymer of the first cushioning material may have a weight average molecular weight of about 10,000 to about 800,000, such as about 25,000 to about 500,000 or about 50,000 to about 250,000.

[0096] When a cushioning material is disposed on the resiliently deformable element, then this cushioning material may be referred to herein as“second cushioning material”.

[0097] The second cushioning material may be disposed on a surface of the resiliently deformable material. The second cushioning material may be disposed on an inner surface or an outer surface of the resiliently deformable element. The outer surface of the resiliently deformable element may rest on the protrusion or press against the protrusion.

[0098] When the second cushioning material is on an outer surface of the resiliently deformable element, it may be brought into contact with the protrusion of the base plate.

[0099] In another example, the second cushioning material is on an inner surface of the resiliently deformable element. When the second cushioning material is on an inner surface of the resiliently deformable element, it may be brought into contact with the PCB. In this arrangement, the second cushioning material may absorb the mechanical impact between the PCB and the part of the resiliently deformable element that rests on the protrusion.

[0100] The second cushioning material may be a layer disposed on the surface of the resiliently deformable material.

[0101] The layer of the second cushioning material may be circular or annular. This layer of the second cushioning material may fit within the resiliently

deformable element. In one example, the layer of the second cushioning material is annular.

[0102] The layer may have a thickness of about 5 mm to about 1 mm, such as about 10 mm to about 500 mm or about 50 mm to about 250 mm.

[0103] The second cushioning material comprises a polymer, which may be selected from a silicone, a polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof.

[0104] In one example, the second cushioning material is a silicone. In a further example, the second cushioning material is a polyester. In another example, the second cushioning material is a polypropylene. In a further example, the second cushioning material is an elastomer.

[0105] The second cushioning material may, for example, comprise a

polyurethane. When the second cushioning material is a polyurethane, then the touch pad assembly may show reduced mechanical wear through repeated use. [0106] The polymer of the second cushioning materia! may have a weight average molecular weight of about 10,000 to about 800,000, such as about 25,000 to about 500,000 or about 50,000 to about 250,000.

[0107] The touch pad assembly may comprise the first cushioning material as, for example, the only cushioning material. The touch pad assembly may comprise the second cushioning material as, for example, the only cushioning material.

[0108] In an example, the touch pad assembly may comprise the first cushioning material and the second cushioning material. When the touch pad assembly comprises a first cushioning material and a second cushioning material, then the first cushioning material may be the same material or a different material to the material of the second cushioning material.

[0109] The switch of the touch pad assembly comprises a first contact and a second contact. The first contact and the second contact may be arranged in a variety of ways.

[0110] The first contact of the switch may be on an underside of the touch pad, such as the PCB. The first contact of the switch may be on a surface of the PCB.

[0111] The first contact may be a PCB contact. This contact may be referred to herein as the“first PCB contact”.

[0112] When pressure is applied to the touch pad, such as by a user pressing the touch pad, then the touch pad is moved from its first position toward its second position to close the switch and form an electrical connection between the first contact and the second contact.

[0113] When the pressure is released from the touch pad, then the resiliently deformable element will drive the opening of the switch to disconnect the electrical connection between the first contact and the second contact. The resiliently deformable element may return the touch pad to its first position.

[0114] Once the first contact has formed an electrical connection with the second contact, further movement of the touch pad may be restricted. Thus, the touch pad may be in its second position.

[0115] In one example, the second contact is located under the first contact. The second contact may be connected to the base plate, the support structure or a housing for the touch pad. Pressing or pushing the touch pad may, for example, move the first contact toward the second contact until an electrical connection is formed. In another example, the resiliently deformable element may be connected to the first contact. Pressing or pushing the touch pad may move the resiliently deformable element toward the second contact until an electrical connection is formed.

[0116] The second contact may be embedded within the housing.

[0117] A peripheral portion of the first contact may be exposed from or through the first cushioning material. This peripheral portion is for forming an electrical connection with either the resiliently deformable element or the second contact.

[0118] A peripheral portion of the resiliently deformable material may be exposed from the second cushioning material. This peripheral portion is for forming an electrical connection with either the first contact or the second contact.

[0119] The second contact may have an exposed contact portion within the housing. This exposed contact portion is for forming an electrical connection with the first contact or the resiliently deformable element. The exposed contact portion may protrude out from a sidewall of the housing.

[0120] In another example, the second contact may be on an underside of the touch pad, such as the PCB. The second contact of the switch may be on a surface of the PCB.

[0121] The second contact may be a PCB contact. This contact may be referred to herein as the“second PCB contact”.

[0122] The first PCB contact and the second PCB contact may be separated on a surface of the PCB. Thus, the first PCB contact and the second PCB contact are positioned on the PCB to be insulated from one another.

[0123] When both the first PCB contact and the second PCB contact are on a surface of the PCB, then the resiliently deformable element may be part of the switch. The resiliently deformable element may be used to provide the electrical connection between the first contact and the second contact. To provide such a connection, the resiliently deformable element may be conductive.

[0124] When pressure is applied to the touch pad, the resiliently deformable element is compressed against the protrusion. A part or all of the resiliently deformable element is directed by the protrusion toward the PCB to form an electrical connection between the first PCB contact and the second PCB contact. The protrusion may direct the resiiiently deformable element toward the first PCB contact, the second PCB contact or both the first PCB contact and the second PCB contact.

[0125] In one example, the first PCB contact may be permanently electrically connected to the resiiiently deformable element. A first end of the resiiiently deformable element may rest on the first PCB contact. The second end of the resiiiently deformable element is for contact with the second PCB contact. Thus, compressing the resiiiently deformable element will bring the resiiiently deformable element into contact with the second PCB contact.

[0126] In another example, the second PCB contact may be permanently electrically connected to the resiiiently deformable element. A first end of the resiiiently deformable element may rest on the second PCB contact. The second end of the resiiiently deformable element is for contact with the first PCB contact. Thus, compressing the resiiiently deformable element will bring the resiiiently deformable element into contact with the first PCB contact.

[0127] In a further example, compressing the resiiiently deformable element will bring both the first PCB contact and the second PCB contact into contact with resiiiently deformable element. In this example, neither the first PCB contact nor the second PCB contact is permanently electrically connected to the resiiiently deformable element.

[0128] The resiiiently deformable element may be disposed on one side on the underside of the touch pad. An opposite side of the touch pad may be hinged. Thus, a hinge may be attached to an edge of the touch pad.

[0129] The hinge supports the touch pad at one side. The hinge allows vertical of the movement of the touch pad at the opposite side, such that when the touch pad is pressed, the underlying resiiiently deformable element is compressed.

[0130] The touch pad assembly may comprise a housing. The housing may be an insulative housing.

[0131] The hinge may be attached to the housing or to the base plate. [0132] The housing may provide a support structure for the touch pad. The housing may be positioned above the base plate or the base plate may form part of the housing.

[0133] The touch pad may be secured to a housing. The housing may direct the movement of the touch pad. Thus, the housing may comprise a channel or a recessed portion to direct vertical movement of the touch pad.

[0134] The housing may comprise a press seat for the touch pad.

Electronic device

[0135] The electronic device of the present disclosure may be a computer, a cell phone, a portable networking device, a portable gaming device or a portable GPS.

[0136] The electronic device may be portable. When the electronic device is portable and is a computer, then the electronic device may be a laptop or a tablet.

[0137] The electronic device comprises a housing. The housing of the electronic device may provide a case or cover for the device.

[0138] The housing contains an electrical circuit, such as a motherboard or display circuitry. The housing may be external to the electrical circuit. The electrical circuit is disposed within the housing.

EXAMPLES

[0139] The present disclosure will now be illustrated by the following non-limiting example.

Example 1

[0140] A touch pad assembly 10 is shown schematically in Figure 1. A cross section through the assembly is shown. To use the touch pad, the user presses a touch pad surface 20, which may, for instance, be made of glass.

[0141] A PCB 30 is attached to an underside of the touch pad surface 20. The PCB contains circuitry to detect a touch operation by the user, such as when the user wishes to move a cursor on a display screen of an electronic device.

[0142] An underside of the touch pad, in this instance PCB 30, is attached to a resiliently deformable element 60. Figure 1 shows a resiliently deformable element, which is, in this instance, a dome shaped metal spring In this example, a first contact 25 is disposed on a surface of PCB 30. First contact 25 is a first PCB contact. The shape of first contact 25 may, for example, be as shown in Figure 3.

[0143] A second contact 15 is disposed, in this instance, on a surface of PCB 30. Second contact 15 is a second PCB contact. Second contact 15 may, for example, be permanently connected to a first end of the dome shaped metal spring. Thus, in this instance, the circular edge of the dome shaped spring rests on the surface of the second PCB contact, which can have an arcuate or annular shape to follow the edge of the spring. The shape of second contact 15 may, for example, be as shown in Figure 3.

[0144] In this example, a cushioning material 40 is disposed as a layer on the surface of PCB 30. This cushioning material is a first cushioning material 40 and, in this instance, has a circular shape. The first cushioning material may, for example, be made of a polyurethane.

[0145] In this example, a cushioning material 50 is also disposed on the resiliently deformable element 60. This cushioning material is a second cushioning material 50 and, in this instance, has an annular shape. The second cushioning material may, for example, be made of a polyurethane. The second cushioning material may be disposed as a layer on an inner surface of dome shaped spring 60.

[0146] The touch pad assembly comprises a housing 80, which contains a base plate 70 having a protrusion 75. The second end of the resiliently deformable element rests on protrusion 75. In this example, the second end is a peak of the dome shaped metal spring.

[0147] When the touch pad is pressed, the touch pad is moved from its first position vertically toward base plate 70. The dome shaped metal spring 60 is compressed between PCB 30 and protrusion 75. As the dome shaped metal spring 60 is compressed, protrusion 75 directs a second end of the spring toward first contact 25 until they are brought into contact with one another. As the first end of the dome shaped spring is, in this instance, permanently connected to second contact 15, when the spring is brought into contact with first contact 25, an electrical connection is formed. When the eiectrical connection is formed, the touch pad is in its second position.

[0148] Without the presence of the first cushioning material 40 and the second cushioning material 50, the impact between PCB 30 and the combination of protrusion 75 on the dome shape spring 60 can generate a noise. This noise can be irritating and may cause a disturbance, especially when the touch pad is pressed repeatedly.

[0149] The first cushioning material 40 and the second cushioning material 50 reduce the noise generated by the impact between PCB 30 and the combination of the dome shaped metal spring 60 and the protrusion 75. The present disclosure can, for example, provide a noiseless touch pad assembly. The cushioning material may also reduce the mechanical wear of the components within the touch pad assembly.

[0150] When the touch pad is released, the dome shaped metal spring restores the touch pad from its second position to its first position, thereby breaking the electrical connection. The electrical connection is broken when the dome shaped metal spring restores itself to its original shape.

[0151] Figure 2 is an exploded 3D projection of an example of the touch pad assembly. A touch pad surface 20 made of, in this instance, a glass plate is disposed on PCB 30. A side of the touch pad may be attached to a hinge 85 that can provide pivotal movement when, for example, the hinge 85 is attached to the housing 80 (only part of the housing is shown). The touch pad is disposed above base plate 70 having a protrusion 75. The base plate may have a connection point 90 for earthing electrical connections.

[0152] Figure 3 also shows an exploded 3D projection of an example of an underside of a touch pad assembly. PCB 30 has, in this instance, a first contact 25 and a second contact 15. In this example, there is a first cushioning material 40 and a second cushioning material 50. The second cushioning material 50 may, for example, rest against an inner surface of the resiliently deformable element 60. The resiliently deformable element 60 is, in this instance, a dome shaped metal spring. [0153] Liners 100 and 110 may, for example, be inserted within the housing of the touch pad assembly. Liners 100 and 110 may assist with supporting and holding the components of the touch pad in place. The liners may, for example, be made of a stretched polyester film.

[0154] Figure 4 shows a simplified cross-section through an example of a touch pad assembly 110. Arrow 200 shows the position at which a user should press the touch pad surface 120. PCB 130 is, for example, attached to a switch 160, which, in this instance, has a dome shaped metal spring as the resiliently deformable element, such as shown in Figure 1. Switch 160 is disposed on one side of the touch pad. In this example, PCB 130 is attached at an opposite side to the switch by a hinge spacer 230 to base plate 170. The touch pad may have pivotal movement about hinge spacer 230 and the touch pad may move vertically at the side where switch 160 is positioned. The base plate 170 has a protrusion 175 that rests under the resiliently deformable element of switch 160. To restrict the vertical movement of the touch pad, a stopper 210 may, for example, be disposed on PCB 130.

[0155] Base plate 170 may be fixed to a support structure 280 by means of screws 285. The combined base plate 170 and the support structure 280 may form part of a housing 180.

Claims

1. A touch pad assembly for an electronic device comprising:

a switch for electrically connecting a first contact with a second contact, a moveable touch pad,

a base plate,

a resiliently deformable element that is connected to an underside of the touch pad and is retained by a protrusion on a base plate,

wherein the switch is operable by the moveable touch pad, and

wherein a cushioning material comprising a polymer is disposed between the underside of the touch pad and the protrusion, and wherein the polymer is selected from a silicone, a polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof.

2. The touch pad assembly of claim 1 , wherein the cushioning material comprises polyurethane.

3. The touch pad assembly of claim 1 , wherein the resiliently deformable element is a compression spring.

4. The touch pad assembly of claim 3, wherein the compression spring is a dome shaped metal spring.

5. The touch pad assembly of claim 1 , wherein the cushioning material is disposed on the resiliently deformable element.

6. The touch pad assembly of claim 1 , wherein the cushioning material is disposed on an underside of the touch pad and within the resiliently deformable element.

7. The touch pad assembly of claim 1 , wherein the cushioning material is a first cushioning material and is disposed on an underside of the touch pad and within the resiliently deformable element, and wherein a second cushioning material is disposed on the resiliently deformable element.

8. The touch pad assembly of claim 7, wherein the second cushioning material comprises a polymer selected from a silicone, a polyurethane, a polyester, a polypropylene, an elastomer and a combination of two or more thereof.

9. The touch pad assembly of claim 8, wherein the second cushioning material comprises a polyurethane.

10. The touch pad assembly of claim 1 , wherein the touch pad comprises a touch pad surface and a printed circuit board (PCB) on an underside of the touch pad surface.

11. The touch pad assembly of claim 10, wherein the first contact of the switch is on the PCB.

12. The touch pad assembly of claim 11, wherein the second contact of the switch is on the PCB.

13. The touch pad assembly of claim 1 , wherein the switch is arranged to form an electrical connection between the first contact and the second contact when the resiliently deformable element is compressed.

14. The touch pad assembly of claim 1 , wherein the resiliently deformable element is metallic and is arranged to form an electric connection between the first contact and the second contact when compressed.

15. An electronic device comprising:

a housing containing an electrical circuit; and

a touch pad assembly according to claim 1 within the housing.