WO2009139762A1

WO2009139762A1 - Wear-resistant touchpads

Info

Publication number: WO2009139762A1
Application number: PCT/US2008/063388
Authority: WO
Inventors: Jeffrey A. Lev; Paul J. Doczy; Earl W. Moore
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2008-05-12
Filing date: 2008-05-12
Publication date: 2009-11-19
Also published as: TW201001257A

Abstract

A touchpad for use with a computing device. The touchpad includes a top layer that defines an outer surface and a durable protective coating that has been directly applied to the upper surface of the top layer.

Description

WEAR-RESISTANT TOUCHPADS

BACKGROUND

Most notebook computers comprise capacitive touch-sensitive pads, commonly referred to as "touchpads," that are used to register user inputs. In many cases, the touchpad may be used as a substitute for a separate mouse. Because the touchpad is integrated into the housing of the computer, greater portability and ease of use are enabled.

Because of their convenience, touchpads are normally used by the computer user on a frequent basis. Such use often wears away the matte finish top surface of the touchpad, resulting in the development of a shiny and/or discolored region, typically in the middle of the touchpad. In addition to reducing computer aesthetics, such wear may adversely affect the sensitivity of the touchpad, potentially to the point at which it no longer functions correctly.

Although protective sheeting has been used in the past in an attempt to reduce touchpad wear, such sheeting reduces the effectiveness of the touchpads to which they are applied. One reason for that reduction may relate to the layer of adhesive that is necessary to attach the sheeting to the touchpad and that layer's effect on the dielectric properties of the touchpad. Another reason may relate to the thickness of the sheeting, which also has an effect on those properties. BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed touchpads can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale.

FIG. 1 is a perspective view of an embodiment of a computing device that incorporates a touchpad to which a durable protective coating has been applied.

FIG. 2 is a schematic view depicting apparatus for applying and curing a durable protective coating.

FIG. 3 is a schematic side view of a touchpad to which a durable protective coating has been applied. FIG. 4 is a flow chart of an embodiment of a method for producing a wear- resistant touchpad.

DETAILED DESCRIPTION

As described above, touchpads are susceptible to wear that can negatively affect the appearance of the computer as well as the functionality of the touchpad.

Although protective sheeting can be applied to reduce such wear, such sheeting often adversely affects the sensitivity of the touchpad. As described in the following, however, increased wear resistance can be attained without the use of protective sheeting when a durable protective coating is applied to the touchpad. In some embodiments, the durable protective coating comprises an ultraviolet (UV) curable coating that is sprayed on the surface of the touchpad.

Turning to the figures, in which like numerals identify corresponding elements, illustrated in FIG. 1 is an embodiment of a computing device 100 configured as a notebook or "laptop" computer. The computing device 100 generally comprises a base portion 102 and a display portion 104. The base portion 102 comprises a housing 106 that contains various internal components of the computing device 100, such as one or more processors, memory, a hard drive, and the like. Also comprised by the base portion 102 is a user interface including a keyboard 108, a capacitive touchpad 110, and selection buttons 112. The display portion 104 also comprises a housing 114 that surrounds a display 116, such as a liquid crystal display (LCD).

The touchpad 110 comprises a durable protective coating (not visible in FIG. 1) that has been applied to the outer surface of the touchpad. Application and characteristics of the coating are described in the following. FIG. 2 illustrates apparatus 200 for applying and curing a durable protective coating. The apparatus includes a conveyor 202 upon which a touchpad module 204 has been provided. The conveyor 202 transports the touchpad module 204 to a position adjacent (e.g., below) a spray apparatus 206 that sprays a UV-curable liquid 208 onto the surface of the touchpad module 204. By way of example, the UV- curable liquid 208 comprises an organic acrylate, a silicone containing acrylate, or a urethane thats include a photoinitiator. After the surface has been coated with the liquid 208, the touchpad module 204 can be transported by the conveyor 202 an oven 210 in which the liquid is cured. By way of example, the liquid 208 is exposed to UV radiation that cures, and therefore hardens, the liquid. Examples of non-UV- curable coatings include acrylics and polyurethanes.

Schematically illustrated in FIG. 3 is a touchpad 300 to which a durable protective coating has been applied. As indicated in FIG. 3, the touchpad 300 includes a substrate 302, which may comprise a circuit board, and a top layer 304 that overlies the substrate 302. The top layer 304 defines an outer surface 306 that typically is exposed so that it may be touched by a user's fingertip to enter an input. By way of example, the top layer 304 is composed of a polymeric material, such as a polyester film. In the embodiment of FIG. 3, however, an outer layer 308 in the form of a durable protective coating has been directly applied to the outer surface 306 of the top layer 304. By way of example, the outer layer 308 is approximately 5 to 25 microns (μm) thick.

Because the durable protective layer (i.e., outer layer 308) is directly sprayed onto the outer surface 306 of the touchpad 300, there is no adhesive layer to alter the dielectric properties of the touchpad. Moreover, because the durable protective layer is so thin, the layer has a minimal effect on the dielectric properties of the touchpad 300 and, therefore, does not significantly affect the operation or use of the touchpad. Despite the thinness of the durable protective layer, significant improvement in wear-resistance is achieved. By way of example, a durable protective coating of the type described above can increase the wear resistance of the touchpad by the factor of 50. FIG. 4 is a flow chart that describes actions of an embodiment of a method for producing a touchpad consistent with the above disclosure. Beginning with block 400, a durable protective coating is sprayed onto the outer surface of a touchpad. Next, the durable protective coating is cured in place on the touchpad surface, as indicated in block 402.

Claims

1. A touchpad for use with a computing device, the touchpad comprising: a top layer that defines an outer surface; and a durable protective coating that has been directly applied to the outer surface of the top layer.

2. The touchpad of claim 1, wherein the top layer is composed of a polymeric material.

3. The touchpad of claim 1 , wherein the durable protective coating is an ultraviolet-curable coating.

4. The touchpad of claim 1 , wherein the durable protective coating is approximately 5 to 25 microns thick.

5. A touchpad for use with a computing device, the touchpad comprising: a substrate; a top layer provided over the substrate, the top layer defining an outer surface of the touchpad; and an ultraviolet-curable durable protective coating that has been directly sprayed onto the outer surface of the top layer.

6. The touchpad of claim 6, wherein the durable protective coating is approximately 5 to 25 microns thick.

7. A computing device comprising: a base portion; a display portion pivotally connected to the base portion; and a user interface provided on the base portion, the user interface including a touchpad having a top layer that defines an outer surface and a durable protective coating that has been directly applied to the outer surface of the top layer.

8. The computing device of claim 7, wherein the top layer of the touchpad is composed of a polymeric material.

9. The computing device of claim 7, wherein the durable protective coating is an ultraviolet-curable coating.

10. The computing device of claim 7, wherein the durable protective coating is approximately 5 to 25 microns thick.

11. A method for producing a touchpad, the method comprising: applying a durable protective coating to an outer surface of the touchpad; and curing the durable protective coating.

12. The method of claim 11 , wherein applying a durable protective coating comprises spraying a liquid onto the outer surface of the touchpad.

13. The method of claim 11 , wherein spraying a liquid comprises spraying an ultraviolet-curable liquid onto the outer surface.

14. The method of claim 11 , wherein curing the durable protective coating comprises exposing the ultraviolet-curable liquid to ultraviolet radiation.