Patent Application
20170336895
Aspects of the disclosure relate to touch sensor devices. More particularly, aspects of the disclosure relate to resistive touch sensor devices comprising first and second sheets separated by a gap,
Of various interfaces available for interacting with a computer system, one of the easiest to use and understand is the touchscreen. This technology allows a user to simply touch an icon or picture to navigate through the system, display the information the user is seeking, and to enter data. For this reason, this technology is widely used in many applications, including desktop computers, tablet computers, mobile devices, bank machines, information kiosks, restaurants, cars, navigation systems, etc.
A number of different conventional touchscreen technologies exist. These methodologies include resistive, capacitive, surface acoustic wave, infrared, and optical touchscreen technology.
Resistive touch sensors, such as those used in touchscreen panels, typically comprise multiple sheets separated by a gap. Typically, one sheet is a hard substrate layer, and the other sheet is a flexible switch layer that, when touched, flexes to touch the substrate layer. Each sheet typically has a surface coated with a conductive layer. The sheets may be substantially transparent. A typical transparent substrate is glass. The conductive layers may be an Indium Tin Oxide (ITO) coating. Alternatively, a fine conductive mesh (such as a metal mesh) or other conductive material may be used for the conductive layer of one or more sheets.
Sensors, typically located at the corners of the touch sensor, may detect differences in voltage or current measured at the sensors that occur when the sensor is touched. The differences in voltage or current will depend on the location of contact of the sheets caused by the touch. Thus, by analyzing the measurements from the sensors, the position of the touch may be computed.
The gap between the conductive layers of the sheets is typically filled with air. Conventional sensors may include “spacer dots” or “microdots” between the substrate and sensor layers to help maintain the gap and separation. The gap may have a periphery or outer perimeter around sides of the sensor (i.e. near side edges of the two sheets) that is sealed to prevent moisture, dust or other contaminants from entering the gap and damaging the sensor or degrading sensor performance. The seal may be a gasket that extends around the outer perimeter of the surfaces of the sheets that face each other.
A conventional sensor may be hermetically sealed. For example, a periphery of the gap may be sealed. The air in the gap may expand and/or contract due to temperature and pressure changes in the touch sensor's environment. The expansion and/or contraction of the air in the gap can cause damage to the sensor. For example, if the air expands too much, the seal for the gap (e.g. a gasket) may rupture and air may escape. Then, if the air contracts, the touch sensor may collapse such that the conductive layers of the sensor sheets are no longer properly separated, In some touchscreen panels, a pressure change in of approximately 100 mbar could be sufficient to cause damage. The chance of sensor failure may be exacerbated if the touch sensor device is not mounted properly in a housing. A gasket or housing for the sensor may not be mounted properly, thereby lowering the temperature or pressure change that could damage the sensor.
A touch sensor with an unsealed or vented gap area may allow air pressure to equalize with the surrounding environment to reduce the chance of failure due to temperature/pressure changes. However, the unsealed or vented sensor may be prone to failure due to contaminants such as dust entering the gap and interfering with the contact between the sheets as well as creating optical deficiencies from such contaminants. Moisture from condensation or cleaning agents can be wicked in through the vent as well which may cause electrical shorting between the conductive layer which can cause erratic operation or a constant touch event. Also, the air gap can also become blocked by mounting such as squeezing it shut by a front foam or rubber gasket needed to seal the sensor in the bezel or housing of the equipment unless special precautions are taken to prevent that from happening.
According to one aspect of the disclosure, there is provided a touch sensor device comprising: a first sheet having a first conductive layer; a second sheet having a second conductive layer overlaying and spaced from the first conductive layer of the first sheet, thereby forming a gap between the first and second sheets, the gap being filled with gas and having a sealed periphery; a hole in the first sheet extending from the gap to an outer surface of the first sheet; and a regulator device comprising an expandable and contractible chamber, the regulator device being connected to the hole to allow flow of the gas between the chamber and the gap.
In some embodiments, the touch sensor device further comprises a conduit connecting the regulator device is connected to the hole allowing said flow of the gas.
In some embodiments, the chamber expands and contracts to regulate pressure of the gas in the gap.
In some embodiments, the chamber comprises a flexible diaphragm that provides said expansion and contraction.
In some embodiments, the diaphragm comprises an elastomeric film.
In some embodiments, the elastomeric film comprises latex.
In some embodiments, the hole extends through the first conductive layer and to the outer surface.
In some embodiments, the outer surface of the first sheet is a side surface between the first surface and a back surface opposite to the first surface.
In some embodiments, the outer surface of the first sheet comprises a back surface opposite to the first surface.
In some embodiments, the first sheet comprises a substrate sheet and the first sheet comprises a switch sheet,
In some embodiments, the second sheet is flexible to contact the first sheet when touched.
In some embodiments, the substrate sheet and the switch sheet are each substantially transparent.
In some embodiments, each of the first and second sheets comprise a conductive coating.
In some embodiments, the device is hermetically sealed.
In some embodiments, the gas comprises air,
According to another aspect of the disclosure, there is provided a method for a resistive touch sensor comprising a first sheet overlaying and spaced from a second sheet to form a gap therebetween filled with gas, the method comprising: providing a hole in the first sheet from the gap to an outer surface of the first sheet; connecting a regulator device comprising an expandable and contractible chamber to the hole to allow flow of the gas between the chamber and the gap.
In some embodiments, said connecting comprises connecting a tube between the hole and the regulator device.
According to another aspect of the disclosure, there is provided a regulator device for a touch sensor comprising a first sheet overlaying and spaced from a second sheet to form a gap therebetween filled with gas, the regulator device comprising: an expandable and contractible chamber; a conduit for connecting the regulator device to a hole in the touch sensor to allow flow of the gas between the chamber and the gap.
In some embodiments, the conduit comprises a tube.
In some embodiments, the chamber expands and contracts to relieve regulate at least one of pressure and volume of the gas in the gap.
Other aspects and features of the present disclosure will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific embodiments of the disclosure.
Some embodiments of the disclosure will now be described in greater detail with reference to the accompanying diagrams, in which:
As discussed above, conventional touch sensor devices having a gap between sheets of the sensor (such as resistive sensors) may fail due to temperature and/or pressure changes that cause expansion or contraction of the air or other gas in the gap. It may be desirable to provide a sealed sensor that includes means for regulating the pressure and/or volume of the air or other gas within the gap between sheets. The term “gas” is used broadly herein to include both a pure gas and a gas mixture, such as air. Embodiments are not limited to any particular gas content within the gap of a resistive sensor.
It is to be understood that references herein to orientations such as “front”, “back”, “side”, “upper”, “lower” etc. or to directions are for ease of description and are not intended to limit the orientation of the embodiments described herein and shown in the figures.
It will be appreciated by a person skilled in the art that various elements of the embodiments shown in the figures are not necessarily shown to scale. For example some elements may be shown enlarged in comparison to other elements for illustrative purposes. The figures are not intended to limit any embodiments to a particular relative sizing of elements.
The substrate layer 102 includes a glass substrate sheet 120 with an ITO conductive coating 122 that faces the switch layer 104. The substrate layer 102 also includes a silver linearity pattern 124 extending around the ITO coating 122 near the sides 106, 108, 110 and 112. The silver linearity pattern 124 is in turn covered by a dielectric protective layer 126. The silver linearity pattern 124 in this example is a conductive array of traces that act like a chain of resistors that interconnect corner electrodes (not shown) on a conventional five wire sensor. The silver linearity pattern 124 may help ensure that when touching close to the edge of the sensor, the touch sensed by the sensor does not wander in towards the center of the sensor such as in a pincushion pattern. The resistor chain formed by the silver linearity pattern 124 may compensate for the anomaly. This type of silver linearity pattern 124 may not be used for a conventional four wire sensor. Other conductive, low ohm materials such as metals, conductive inks or other coatings may also be used for a linearity pattern rather than silver.
Spacer dots 128 are provided on the substrate layer 102 to maintain an air gap 130 between the substrate layer 102 and the switch layer 104. A narrow gasket 132 seals the gap 130 around its periphery (i.e. at the sides 106, 108, 110 and 112).
The arrangement and specific materials and components of the touch sensor 100 in
Substrate and switch layers (such as the substrate and switch layers 104 and 102 described above) may be referred to as sheets herein, where it is to be understood that the substrate and switch sheets may include conductive layers that face each other.
The touch sensor device 300 further includes a hole 314, that functions as a port, in the substrate sheet 302. The hole 314 that extends from the air gap 306 (at the first surface 310) to the side surface 316 of the substrate sheet 302. In other embodiments, the hole 314 may extend to a different outer surface (such as a different side, or to the back/IoN,ver surface 318 that is opposite to the first surface 310). The hole 314 includes a 90 degree bend 320 such that the hole extends downward from the first surface 310 and then turns to the side surface 318. However, the arrangement, shape, width and length of the hole may vary in other embodiments. Any hole, port or aperture that extends between an outer surface and the air gap 306 may be used.
The touch sensor device 300 further includes a regulator device 322. The regulator device 322 defines a chamber 324 that is filled with air. The touch sensor device 300 also includes a tube 326 connected between the chamber 324 and the hole 314 in the substrate sheet 302 such that air can flow between the chamber 326 and the air gap 306 between the substrate sheet 302 and the switch sheet 304, The chamber 324 in this example is formed by a generally cylindrical chamber housing 328 including chamber bottom 330 and circular chamber periphery 332. The chamber housing may be in another shape, such as a box shape, in other embodiments. A diaphragm 334 forms an upper wall or top of the chamber housing 328. The diaphragm 334 in this example is a flexible elastomeric film, such as latex. Other flexible materials, such as low durometer materials, that are gas impermeable (and possibly hydrogen impermeable) may also be used. The thickness of the diaphragm may vary. For a latex film diameter, the film thickness may be 0.1 mm, for example. The diaphragm 334 is flexible to allow expansion and contraction of the chamber 324. The diaphragm housing 328 may be made of any air-impermeable material including but not limited to hard plastic or rubber,
Any embodiment similar in operation to the diaphragm-type regulator device 322 described herein may be used. For instance, a bag that has sufficient surface rigidity or other spring device assistance that allows it to resist inflation or deflation may be used. Also, a bellows or accordion type device that resists inflation or deflation may also be used.
The tube 326 may be connected in a sealed manner to the hole 314 and to the regulator device 322. The assembled touch sensor device 300 may be hermetically sealed. The tube may be a catheter made plastic or any other suitable impermeable material. The catheter may be approximately 1mm in diameter, for example but any suitable size of tubing that allows sufficient air movement can be used. Any method for securing the tube 326 between the hole 314 and the regulator device 322 may be used including, but not limited to, sealants and/or adhesives, gasket(s), etc. The tube 326 may also be melted or welded to form the sealing attachment to the hole 314 and/or the regulator device 322. As another example, the tube 326 may be formed integrally with the chamber housing 328, The tube 326 may be made of any air-impermeable material including but not limited to plastic or rubber. In still other embodiments, the tube 326 may be omitted and other means of connecting the regulator device 322 to the touch sensor 301 may be used. For example, other conduits such as a pipe, or extension from the substrate sheet may extend into an inlet in the regulator device. Any suitable means to provide the air flow connection to the chamber from the air gap may be used.
The diaphragm 334 may be more flexible than the switch sheet 304, such that the volume of the chamber 324, rather than the air gap 306, changes in response to changes in temperature and pressure of the surrounding environment. Thus, when the air in the touch sensor device 300 expands, excess air may be vented from the air gap 306 to the chamber 324 of the regulator device 32. The chamber 324 expands due to the flexibility of the diaphragm 334. Similarly, if air within the touch sensor device 300 contracts, air may flow from the chamber 324 of the regulator device 322 to the air gap 306.
The regulator device 322 shown in
Embodiments are not limited to the diaphragm-type regulator device 322 shown in
The size and volume of gas held by the chamber of a regulator device (such as regulator device 322 in
In some embodiments, the regulator device described herein (such as the regulator device 300 or 400 shown in
It is to be understood that a combination of more than one of the approaches described above may be implemented. Embodiments are not limited to any particular one or more of the approaches, methods or apparatuses disclosed herein. One skilled in the art will appreciate that variations, alterations of the embodiments described herein may be made in various implementations without departing from the scope of the claims.
