Existing digital resistive touchscreen designs utilize a number of horizontal and vertical oriented Indium-Tin-Oxide (ITO) resistive tracks. Where the ITO tracks intersect is called a “touchell”. These touchells are typically large, approximately 12.7 mm by 12.7 mm (0.5 inches×0.5 inches). This large size is required to limit the number of traces providing interconnect around the perimeter of the touch screen area. Touch detection is achieved through digital scan, which is quick but lacks granularity, and/or analog scan, which offers good measurement granularity and positional data but requires slower analog to digital conversion and data processing. Digital scan and analog scan have been used together to quickly detect a touch using digital scan then performing a more intensive and accurate analog scan in the detected area to precisely locate the touch.
These methods allow a relatively low resolution digital resistive touch screen to provide high resolution positional data, but the scans, data acquisition, and processing take significant time to accomplish. Furthermore, the silver epoxy traces used around the perimeter to provide interconnect add resistance to the analog measurement which degrades accuracy and must be factored out using the touch controller software. Verifying such complex software can be expensive.
In one aspect, embodiments of the inventive concepts disclosed herein are directed to a touchscreen device utilizing digital scan to resolve a touch location with high precision. The touchscreen device includes touchells of about 3.175 mm by 3.175 mm (0.125 inches by 0.125 inches). An integrated circuit detects contacts in the touchells that resolve to touches on the touchscreen, and communicates those touches to a micro-controller via a serial bus. In a further aspect, silver epoxy interconnects for the tracks are reduced or eliminated.
In a further aspect, multiple touchscreens having distinct touchell networks are disposed to create a larger touchscreen area. Similarly, a single touchscreen may be divided quadrants, each with a distinct touchell network.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and should not restrict the scope of the claims. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the inventive concepts disclosed herein and together with the general description, serve to explain the principles.
The numerous advantages of the embodiments of the inventive concepts disclosed herein may be better understood by those skilled in the art by reference to the accompanying figures in which:
Before explaining at least one embodiment of the inventive concepts disclosed herein in detail, it is to be understood that the inventive concepts are not limited in their application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description or illustrated in the drawings. In the following detailed description of embodiments of the instant inventive concepts, numerous specific details are set forth in order to provide a more thorough understanding of the inventive concepts. However, it will be apparent to one of ordinary skill in the art having the benefit of the instant disclosure that the inventive concepts disclosed herein may be practiced without these specific details. In other instances, well-known features may not be described in detail to avoid unnecessarily complicating the instant disclosure. The inventive concepts disclosed herein are capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
As used herein a letter following a reference numeral is intended to reference an embodiment of the feature or element that may be similar, but not necessarily identical, to a previously described element or feature bearing the same reference numeral (e.g., 1, 1a, 1b). Such shorthand notations are used for purposes of convenience only, and should not be construed to limit the inventive concepts disclosed herein in any way unless expressly stated to the contrary.
Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of the “a” or “an” are employed to describe elements and components of embodiments of the instant inventive concepts. This is done merely for convenience and to give a general sense of the inventive concepts, and “a” and “an” are intended to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
Finally, as used herein any reference to “one embodiment,” or “some embodiments” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the inventive concepts disclosed herein. The appearances of the phrase “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment, and embodiments of the inventive concepts disclosed may include one or more of the features expressly described or inherently present herein, or any combination of sub-combination of two or more such features, along with any other features which may not necessarily be expressly described or inherently present in the instant disclosure.
Broadly, embodiments of the inventive concepts disclosed herein are directed to a touchscreen device utilizing digital scan to resolve a touch location with high precision. The touchscreen device includes touchells of about 3.175 mm by 3.175 mm (0.125 inches by 0.125 inches). An integrated circuit detects contacts in the touchells that resolve to touches on the touchscreen, and communicates those touches to a micro-controller via a serial bus. In a further aspect, silver epoxy interconnects for the tracks are reduced or eliminated. In a further aspect, multiple touchscreens having distinct touchell networks are disposed to create a larger touchscreen area. Similarly, a single touchscreen may be divided quadrants, each with a distinct touchell network.
Referring to
In at least one embodiment, the vertical tracks may be spaced 3.175 mm (0.125 inches) or less apart; likewise, the horizontal tracks may be spaced 3.175 mm (0.125 inches) or less apart. Narrow spacing may allow contacts identified via digital scan to closely resolve the location of a touch without the need for an analog scan. Removing analog scan eliminates the need for complicated algorithms for determining where the touch occurred.
Reducing the touchell size reduces parasitic capacitance of the sensed tracks, allowing for shortened settling times, faster scans, and reducing overall touch detection latency. Existing resistive touch screens include silver epoxy conductors which are a source of excess resistance that must be accounted for during analog scan; placing tracks closer together would cause electrical interference in the silver epoxy conductors during analog scan. Because embodiments of the present disclosure do not employ analog scan, such interference is obviated.
Each of the vertical track printed wiring board 104 and horizontal track printed wiring board 106 and connected to a processor via a serial interface. The interconnects 108, 110 may comprise tapes or flexes that provide interconnect to the high density ITO track matrix 102 though anisotropic conductive film bonding techniques.
Referring to
Referring to
The switch network 302 is in data communication with a programmable comparator network 306 that sends and receives signals to and from the switch network 302. The programmable comparator network 306 identifies one or more tracks where a touch has produced a contact with reference to a programmable voltage reference 308 connected to the programmable comparator network 306 and switch network 302. In at least one embodiment, the programmable comparator network 306 identifies a plurality of electrical contacts in the switch network 302. At least a subset of the plurality of electrical contacts may be identified as a cluster involving a single touch event but multiple, closely spaced electrical contracts.
In at least one embodiment, a serial controller 304 connected to the switch network 302 and programmable comparator network 306 sends signals to the programmable comparator network 306 and switch network 302 according to a plurality of position strapping inputs 310 and serial bus inputs. In at least one embodiment, passthrough features such as a voltage passthrough, return passthrough, and one or more serial bus features may allow interconnect between multiple independent devices.
Multiple integrated circuits 300 may be used to scale to larger touch screens. The serial bus features may be used to control each integrated circuit 300, transfer data representing touch detection, apply threshold programming, enact device mode select, etc. Each integrated circuit 300 may be hardware strap-able to allow all integrated circuits 300 to share the same serial bus. Each integrated circuit 300 may utilize the passthrough features to simplify routing and minimize silver epoxy traces. Integrated circuit attachment could be accomplished via processes similar to existing source driver/board bonding techniques or chip on glass techniques.
In at least one embodiment, the touch screen may be driven from only two sides instead of four. Alternatively, the touch screen may be driven from three sides for redundant applications.
Referring to
In at least one embodiment, each ITO track matrix 400, 402 can always resolve two touches, but in some circumstances may not be able to resolve more than two touches. Three touches can be detected in a non-redundant configuration, but a fourth touch could cause ghosting issues, so the third touch may be used as a fault condition and blocked to prevent fourth touch anomalies. Certain scanning techniques may increase detectable touch quantity. In at least one embodiment, the two or more ITO track matrices 400, 402 are disposed to serve different sections of a singular display; for example, the two or more ITO track matrices 400, 402 may be disposed side-by-side or covering quadrants of the singular display. Each of the two or more ITO track matrices 400, 402 can separately resolve at least two touches independently.
In at least one embodiment, because interconnects are not necessary on opposing sides of a singular integrated circuit, integrated circuits may be placed around the entire perimeter of the touchscreen and the touchscreen electrically broken up into quadrants, allowing each quadrant to operate independently, decreasing scan time further but at the cost of more interconnect.
Referring to
Embodiments of the present disclosure allow for a much higher intrinsic hardware resolution while using a simple and fast digital scan to detect touches.
Embodiments of the present disclosure may minimize the frame around the display reducing weight. Furthermore, silver epoxy traces are applied by a silkscreen process and vary in thickness and length producing different cross-sectional areas which hinder analog scan processes.
It is believed that the inventive concepts disclosed herein and many of their attendant advantages will be understood by the foregoing description of embodiments of the inventive concepts disclosed, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the broad scope of the inventive concepts disclosed herein or without sacrificing all of their material advantages; and individual features from various embodiments may be combined to arrive at other embodiments. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes. Furthermore, any of the features disclosed in relation to any of the individual embodiments may be incorporated into any other embodiment.
Number | Name | Date | Kind |
---|---|---|---|
5159159 | Asher | Oct 1992 | A |
5392058 | Tagawa | Feb 1995 | A |
5534892 | Tagawa | Jul 1996 | A |
8330741 | Camarota | Dec 2012 | B1 |
8421772 | Li | Apr 2013 | B2 |
8519965 | Cady | Aug 2013 | B2 |
8587557 | Lin et al. | Nov 2013 | B2 |
8599565 | Kondoh | Dec 2013 | B2 |
8947393 | Hwang | Feb 2015 | B2 |
8982092 | Lee | Mar 2015 | B2 |
9081450 | Mohindra | Jul 2015 | B1 |
9134827 | Small | Sep 2015 | B2 |
9372509 | Chang | Jun 2016 | B2 |
9612677 | Brunet | Apr 2017 | B2 |
9710095 | Hotelling et al. | Jul 2017 | B2 |
10001894 | Papakostas | Jun 2018 | B2 |
10275078 | Harwood | Apr 2019 | B1 |
10474304 | Gallardo | Nov 2019 | B1 |
10908729 | Hotelling | Feb 2021 | B2 |
20020149572 | Schulz | Oct 2002 | A1 |
20060097991 | Hotelling et al. | May 2006 | A1 |
20090267903 | Cady | Oct 2009 | A1 |
20100321214 | Wang | Dec 2010 | A1 |
20110122088 | Lin et al. | May 2011 | A1 |
20120212425 | Schmidt et al. | Aug 2012 | A1 |
20130015906 | Yeh | Jan 2013 | A1 |
20130127739 | Guard | May 2013 | A1 |
20130207924 | Mohindra | Aug 2013 | A1 |
20150242022 | Hung | Aug 2015 | A1 |
20160054844 | Lin et al. | Feb 2016 | A1 |
20160188098 | Her | Jun 2016 | A1 |
20170131809 | Lin | May 2017 | A1 |
20170139521 | Mosier | May 2017 | A1 |
20170153739 | Ahn | Jun 2017 | A1 |
20190087042 | Ostrand et al. | Mar 2019 | A1 |
20200190372 | Kim | Jun 2020 | A1 |
20200241670 | Abu Saude | Jul 2020 | A1 |
Number | Date | Country |
---|---|---|
102012220093 | May 2013 | DE |
2010016736 | May 2010 | WO |
Entry |
---|
Extended Search Report in European Application No. 21218225.7 dated May 20, 2022, 10 pages. |
Number | Date | Country | |
---|---|---|---|
20220214793 A1 | Jul 2022 | US |