Patent Application
20140035830
The present disclosure relates generally to a device and method of a touch sensor and more particularly to eliminating shadowing for the touch sensor that incorporates a pressure measurement.
An electronic device may incorporate a variety of different input technologies. For example, the electronic device may include a keypad to allow a user to enter inputs. In another example, the electronic device may include a touch sensor that enables a user to enter inputs. Conventional touch technologies include many different types, each with its own set of advantages and disadvantages. A fundamental reason for the different types of touch technologies is that different interpretation methods are used to detect touch inputs. For example, capacitive touch screens interpret a human touch as a change in capacitance measured by the touch panel and resistive touch screens interpret a human touch as a change in resistance measured by the touch panel.
An input entered through a touch screen consists of three degrees of freedom: position, time, and force. However, conventional touch screens sense only two of the three possible degrees of freedom of touch input, namely position and time. Much of the information in the third dimension of force is not captured during touch detection. This partial recognition of user input results in less intuitive interpretations and more cumbersome touch inputs.
Accordingly, there is a need for a touch sensor that eliminates the shadowing effect when the touch sensor is configured to receive multiple touch inputs, including the force parameter.
The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views, together with the detailed description below, are incorporated in and form part of the specification, and serve to further illustrate embodiments of concepts that include the claimed invention, and explain various principles and advantages of those embodiments.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.
A device and method of the present invention relates to eliminating a shadowing effect on a touch input receiving device. The method comprises receiving a touch input on a top side of a top layer of a touch input receiving device, the top layer including a first plurality of conducting lines on a bottom side of the top layer, a first current having a first value passing through the first plurality of conducting lines; and determining a location of the touch input on the touch input receiving device as a function of the first current passing through an intermediate layer of the touch input receiving device as a second current having a second value to a second plurality of conducting lines orthogonal to the first plurality of conducting lines on a top side of a bottom layer of the touch input receiving device, wherein the intermediate layer has a top side and a bottom side, the top side of the intermediate layer disposed adjacent the bottom side of the top layer and the bottom side of the intermediate layer disposed adjacent the top side of the bottom layer, the intermediate layer configured as a resistive layer applying a resistance value to the first current upon the touch input being received, wherein the first current continues through the first conducting lines along a remainder thereof as a third current having a third value after passing through the intermediate layer to eliminate the shadowing effect by enabling a further touch input to be received on the top side of the top layer along the remainder of the first conducting lines.
The exemplary embodiments may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The exemplary embodiments describe a device and method for a touch sensor configured to detect multiple degrees of freedom in a touch input. Specifically, the touch screen is configured to determine a position, a time, and a force of the touch input on the touch screen. As will be described in further detail below, the touch screen is further configured to eliminate a shadowing effect associated with a touch input including the force parameter of the touch input. The touch screen, the components thereof, the degrees of freedom, the shadowing effect, the elimination thereof, and a related method will be discussed in further detail below.
In a specific exemplary embodiment of the present invention, the top layer 105 may include a transparent conducting layer/traces such as indium tin oxide (ITO) and a flexible transparent material such as polyethylene terephthalate layer (PET) while the bottom layer 110 may include a transparent conducting layer/traces such as ITO. However, it should be noted that the use of ITO and PET as described in the present application is exemplary only. The bottom ITO, the top ITO, and the PET may represent any substantially similar layers that are capable of performing the functions of the ITO and the PET. Thus, the ITO may represent any transparent conducting layer or conducting trace while the PET may represent any flexible transparent material. It should also be noted that the ITO may also be made with a non-transparent material such as a metal trace but in a thin enough width (e.g., 5 microns or less) so that it is nearly invisible.
The intermediate layer 205 may be any resistive layer that provides a finite resistance for the current flowing through the conducting lines 120, 125 when a touch input is received. According to a first exemplary embodiment of the present invention, the intermediate layer 205 may be a force sensing layer that is transparent or non-transparent based upon the application or use related to the touch sensor 200. Thus, in a specific exemplary embodiment, the intermediate layer 205 may consist of a transparent conducting oxide (TCO) nano particles dispersed in a transparent polymer matrix. As a result, the TFS 215 is configured so that the resistance thereof becomes highly sensitive to pressure near the composition of a percolation threshold. According to a second exemplary embodiment, the intermediate layer 205 may be a piezo-resistive layer. Thus, the piezo-resistive layer may provide a piezoresistive effect when a mechanical stress is applied on the top layer 105 for a touch input that is received. It should be noted that the intermediate layer 205 may represent any resistive layer that provides a resistance to the current flowing through the conducting lines 120, 125. For example, [can you please provide other examples of a resistive layer?]. It should also be noted that the intermediate layer 205 may be a variable resistive layer. That is, as a function of the pressure being applied on the top side of the top layer 105 from the touch input, the resistance value applied to a current passing therethrough may change as a function of the pressure value.
According to the exemplary embodiments of the present invention, the pressure on the touch sensor 200 is measured by the resistance change upon applied pressure on the top layer 105. Utilizing a hybrid operating mode for more than one touch input (e.g., light touches and hard presses), the resistance of each individual pixel first decreases from the contact area increasing, which is a result from the applied pressure of the touch action. The intermediate layer 205 is configured to be very sensitive to small forces that may be indicative of light touches. Furthermore, with at least one of the layers of the touch sensor 200 being pixilated, the contact area may quickly saturate under a small amount of pressure. Accordingly, a further part of the percolation measurement is present. Specifically, as the resistance of the intermediate layer 205 is highly sensitive to pressure near the composition of the percolation threshold, applied pressure leads to small deformations, thereby resulting in a resistivity decrease. This mode of operation is more sensitive in the higher force range when the contact area is saturated. However, the polymer matrix deformation has only started. Thus, depending on, for example, a Young's modulus of the polymer matrix, the polymer of the intermediate layer 205 may be adjusted so that the contact mode (i.e., for light touch) and the percolation mode (i.e., for hard press) make a smooth transition.
The processor 203 may be configured to receive a current from the conducting lines 120, 125. The processor 203 may further be configured to determine when a touch input is received from the values of the current flowing through the conducting lines 120, 125. When no touch input is received, a first current having a first value may continuously flow through the conducting lines 120. The first current having the first value may be indicative of no touch input being received, thereby the processor 203 interpreting this as no touch input. When a touch input is received, the intermediate layer 205 provides a finite resistance that alters the current flowing through the conducting lines 120, 125. Accordingly, when a touch input is received, a short circuit is generated at the cross points of the conducting lines 120, 125. The current flowing through the intermediate layer 205 generates a second current having a second value flowing through a remainder of the conducting lines 120. Furthermore, the current flows through the short circuit. Thus, the current flowing through the intermediate layer 205 generates a third current having a third value flowing through the conducting lines 125 at the cross points of the touch input. The processor 203 may receive the third current having the third value from the conducting lines 125 to indicate that the touch input is received at those cross points. The second current having the second value flowing through the remainder of the conducting lines 120 allows for the shadowing effect to be eliminated as a further touch input may be received on the conducting lines 120 to generate a further short circuit.
Thus, in an exemplary embodiment in which a further touch input is received, the second current having the second value flowing through the remainder of the conducting lines 120 may allow for the further touch input to be received which would otherwise be located in an area of the touch sensor 200 having a conventional shadowing effect. When the further touch input is received on an area of the remainder of the conducting lines 120 which received the first touch input, the second current having the second value flows through the intermediate layer 205 at the cross points of the further touch input. Subsequently, the second current having the second value continues through a further remainder of the conducting lines 120 as a fourth current having a fourth value. The short circuit generated by the further touch input allows for the second current having the second value to flow through the intermediate value so that a fifth current having a fifth value to flow through the conducting lines 125. The processor 203 may receive the fifth current having the fifth value to determine that the further touch input is received.
In step 1005, a current is generated through the conducting lines 120 of the top layer 105. As described above, a bottom surface of the top layer 105 may include a first set of conducting lines 120. The conducting lines 120 may be configured so that the current flows therethrough.
In step 1010, the processor 203 determines if a touch input is received on a top surface of the top layer 105. When the current remains constant through the conducting lines 120, the processor 203 may determine that no touch input is received. Furthermore, the processor 203 may not receive a current value from the conducting lines 125 since no short circuit is created between the conducting lines 120, 125. However, according to the exemplary embodiments, when the touch input is received, the current flowing through the conducting lines 120 may change from flowing through the intermediate layer 205 and the conducting lines 125 may include a current flowing therethrough at the cross points of the conducting lines 120, 125 at the location where the touch input is received. Thus, when the touch input is received, the method 1000 continues to step 1015.
In step 1015, a first modified current is generated through the conducting lines 125 of the bottom layer 110. As discussed above, the short circuit between the conducting lines 120, 125 allows for the current passing through the conducting lines 120 to flow through the conducting lines 125. As the current passes through the intermediate layer 205, the current flowing through the intermediate layer 205 generates the first modified current. Accordingly, in step 1020, the processor 203 is configured to determine the location of the touch input.
In step 1025, as a further consequence of the short circuit created from the touch input, a second modified current is generated through the conducting lines 120 of the top layer 105. Specifically, the current passing through the conducting lines 120 of the top layer 105 in step 1005 passes through the intermediate layer 205. Consequently, the current flowing through the intermediate layer 205 further generates the second modified current. The second modified current enables the shadowing effect to be eliminated as a further touch input may be received on the remainder of the conducting lines 120.
It should be noted that upon the current being generated through the conducting lines 120 of the top layer 105 in step 1005 may result in steps 1015 and 1025 in which the first and second modified currents are generated. That is, the first and second modified currents may automatically be generated as a result of the short circuit from the touch input being received in step 1010. Furthermore, it should be noted that upon the touch input being completed (e.g., finger raised off the top surface of the top layer 105), the current generated in step 1005 may again resume flowing through the conducting lines 120. As the current is no longer being passed through the intermediate layer 205, the current is not modified.
In step 1030, the processor 203 determines if a further touch input is received. When a further touch input is received, the method 1000 returns to step 1010. As discussed above, the first touch input being received results in various currents passing through the conducting lines 120, 125. Thus, the first touch input includes a first current having a first value originally passing through the conducting lines 120. When the first touch input is received, the first current having the first value is altered from passing through the intermediate layer 205. Accordingly, a second current having a second value passes through the conducting lines 125 of the bottom layer 110 (from the short circuit) while a third current having a third value passes through the remainder of the conducting lines 120 of the top layer 105. When a second touch input is received on the remainder of the conducting lines 120 of the top layer 105, the third current having the third value is altered again from passing through the intermediate layer 205. Accordingly, a fourth current having a fourth value passes through the conducting lines 125 of the bottom layer 110, thereby the processor 205 being configured to determine the location of the second touch input (step 1020 upon second run of the steps 1010-1030). A fifth current having a fifth value passes through a further remainder of the conducting lines 120 of the top layer 105. Thus, the shadowing effect is continuously eliminated as any number of touch inputs are capable of being received on the remainder of the conducting lines 120.
The exemplary embodiments of the present invention provide a touch sensor that is configured for determining all three degrees of freedom of a touch input and eliminate a shadowing effect. In particular, the touch sensor is capable of determining a pressure of the touch input and maintain the capability of receiving a further touch input at all other areas of the touch sensor. An intermediate layer may be disposed between a top layer and a bottom layer that provides a finite resistance to conducting lines of the top and bottom layer. Specifically, the intermediate layer may provide a highly resistive force sensing layer so that a conventional on/off switch configuration of the touch sensor is no longer utilized which otherwise creates the shadow from a touch input including a force parameter.
In the foregoing specification, specific embodiments have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings.
The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.
Moreover in this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “has”, “having,” “includes”, “including,” “contains”, “containing” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a”, “has . . . a”, “includes . . . a”, “contains . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, contains the element. The terms “a” and “an” are defined as one or more unless explicitly stated otherwise herein. The terms “substantially”, “essentially”, “approximately”, “about” or any other version thereof, are defined as being close to as understood by one of ordinary skill in the art, and in one non-limiting embodiment the term is defined to be within 10%, in another embodiment within 5%, in another embodiment within 1% and in another embodiment within 0.5%. The term “coupled” as used herein is defined as connected, although not necessarily directly and not necessarily mechanically. A device or structure that is “configured” in a certain way is configured in at least that way, but may also be configured in ways that are not listed.
It will be appreciated that some embodiments may be comprised of one or more generic or specialized processors (or “processing devices”) such as microprocessors, digital signal processors, customized processors and field programmable gate arrays (FPGAs) and unique stored program instructions (including both software and firmware) that control the one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of the method and/or apparatus described herein. Alternatively, some or all functions could be implemented by a state machine that has no stored program instructions, or in one or more application specific integrated circuits (ASICs), in which each function or some combinations of certain of the functions are implemented as custom logic. Of course, a combination of the two approaches could be used.
Moreover, an embodiment can be implemented as a computer-readable storage medium having computer readable code stored thereon for programming a computer (e.g., comprising a processor) to perform a method as described and claimed herein. Examples of such computer-readable storage mediums include, but are not limited to, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a PROM (Programmable Read Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read Only Memory) and a Flash memory. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.
The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.
