News Column

Patent Application Titled "Touch Screen Sensor" Published Online

August 28, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors Frey, Matthew H. (Cottage Grove, MN); Robrecht, Michael J. (Shorewood, WI); Jambor, George F. (Slinger, WI), filed on February 6, 2014, was made available online on August 14, 2014.

The assignee for this patent application is 3m Innovative Properties Company.

Reporters obtained the following quote from the background information supplied by the inventors: "Touch screen sensors detect the location of an object (for example a finger or a stylus) applied to the surface of a touch screen display or the location of an object positioned near the surface of a touch screen display. These sensors detect the location of the object along the surface of the display, for example in the plane of a flat rectangular display. Examples of touch screen sensors include capacitive sensors, resistive sensors, and projected capacitive sensors. Such sensors include transparent conductive elements that overlay the display. The elements are combined with electronic components that use electrical signals to probe the elements in order to determine the location of an object near or in contact with the display.

"In the field of touch screen sensors, there is a need to have improved control over the electrical properties of the transparent touch screen sensors, without compromising optical quality or properties of the display. A transparent conductive region of a typical touch screen sensor includes a continuous coating of a transparent conducting oxide (TCO) such as indium tin oxide (ITO), the coating exhibiting electrical potential gradients based on the location or locations of contact to a voltage source and the overall shape of the region. This fact leads to a constraint on possible touch sensor designs and sensor performance, and necessitates such measures as expensive signal processing electronics or placement of additional electrodes to modify the electrical potential gradients. Thus, there is a need for transparent conductive elements that offer control over electrical potential gradients that is independent of the aforementioned factors.

"There is an additional need in the field of touch screen sensors that relates to flexibility in the design of electrically conductive elements. The fabrication of touch screen sensors using patterned transparent conducting oxides (TCO) such as indium tin oxide (ITO) often places limitations on conductor design. The limitations relate to a constraint caused by patterning all of the conductive elements from a transparent sheet conductor that has a single value of isotropic sheet resistance."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "The present disclosure relates to touch screen sensors having varying sheet resistance. In a first embodiment, a touch screen sensor includes a visible light transparent substrate and an electrically conductive micropattern disposed on or in the visible light transparent substrate. The micropattern includes a first region micropattern within a touch sensing area and a second region micropattern. The first region micropattern has a first sheet resistance value in a first direction, is visible light transparent, and has at least 90% open area. The second region micropattern has a second sheet resistance value in the first direction. The first sheet resistance value is different from the second sheet resistance value.

"In another embodiment, a touch screen sensor includes a visible light transparent substrate and an electrically conductive micropattern disposed on or in the visible light transparent substrate. The micropattern includes a first region micropattern within a touch sensing area, the first region micropattern having an anisotropic first sheet resistance, being visible light transparent, and having at least 90% open area.

"In another embodiment, a touch screen sensor includes a visible light transparent substrate and an electrically conductive micropattern disposed on or in the visible light transparent substrate. The micropattern includes a first region micropattern within a touch sensing area and a second region micropattern. The electrically conductive micropattern has metallic linear electrically conductive features with a thickness of less than 500 nanometers and a width between 0.5 and 5 micrometers. The first region micropattern has a first sheet resistance value in a first direction between 5 and 500 ohm per square, is visible light transparent, and has between 95% and 99.5% open area. The second region micropattern has a second sheet resistance value in the first direction. The first sheet resistance value is different from the second sheet resistance value.

"In a further embodiment, a touch screen sensor includes a visible light transparent substrate and an electrically conductive micropattern disposed on or in the visible light transparent substrate. The micropattern includes a first region micropattern within a touch sensing area. The electrically conductive micropattern includes metallic linear electrically conductive features having a thickness of less than 500 nanometers and a width between 0.5 and 5 micrometers. The first region micropattern has an anisotropic first sheet resistance with a difference in sheet resistance values for orthogonal directions of a factor of at least 1.5, is visible light transparent, and has between 95% and 99.5% open area.

BRIEF DESCRIPTION OF THE DRAWINGS

"The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:

"FIG. 1 illustrates a schematic diagram of a touch screen sensor 100;

"FIG. 2 illustrates a perspective view of a conductive visible light transparent region lying within a touch screen sensing area;

"FIG. 3 illustrates the conductor micropattern for one embodiment of the touch screen sensor;

"FIG. 4 illustrates a portion of the conductor micropattern illustrated in FIG. 3, the portion including a conductive mesh with selective breaks for modulating the local sheet resistance as well as a larger feature in the form of a contact pad;

"FIG. 5 is a circuit diagram that approximates the properties of the conductor micropattern illustrated in FIG. 3, where capacitive plates are separated by resistive elements;

"FIG. 6 illustrates a modulation in resistance along the horizontal mesh bars given in FIG. 3, created by selective breaks in the contiguous mesh;

"FIG. 7 illustrates the conductor micropattern for one embodiment of the touch screen sensor, the micropattern including regions labeled 7a-7e with different sheet resistance created in part by selective breaks in the electrically conductive micropattern mesh;

"FIGS. 7a-7e each illustrate a portion of the varying conductor micropattern illustrated in FIG. 7;

"FIG. 8 illustrates the distribution of resistance per unit length along the long axis of the wedge-shaped transparent conductive region having regions 7a and 7b therein, as compared with the resistance per unit length for a similarly shaped region comprising only a uniform transparent conducting oxide, ITO;

"FIG. 9 illustrates the arrangement of layers that are laminated together to form one embodiment of the touch screen sensor, an X-Y grid type projected capacitive touch screen sensor;

"FIG. 10 illustrates the conductor micropattern for the X-layer or the Y-layer of an embodiment of the touch screen sensor according to FIG. 9;

"FIG. 11 illustrates a portion of the conductor micropattern illustrated in FIG. 10, the portion including a visible light transparent conductive mesh contacting a larger feature in the form of a contact pad, as well as electrically isolated conductor deposits in the space between the mesh regions;

"FIG. 12 illustrates the conductor micropattern for the X-layer or the Y-layer of another embodiment of the touch screen sensor according to FIG. 9;

"FIG. 13 illustrates a portion of the conductor micropattern given in FIG. 12, the portion including a visible light transparent conductive mesh contacting a larger feature in the form of a contact pad, as well as electrically isolated conductor deposits in the space between the mesh regions;

"FIG. 14 illustrates the conductor micropattern for the X-layer or the Y-layer of another embodiment of the touch screen sensor according to FIG. 9; and

"FIG. 15 illustrates a portion of the conductor micropattern given in FIG. 14, the portion including a visible light transparent conductive mesh contacting a larger feature in the form of a contact pad, as well as electrically isolated conductor deposits in the space between the mesh regions.

"FIGS. 16, 16a, and 16b illustrate various portions of a first patterned substrate;

"FIGS. 17, 17a, and 17b illustrate various portions of a second patterned substrate;

"FIG. 18 illustrates a projected capacitive touch screen transparent sensor element constructed from the first and second patterned substrates of FIGS. 16 and 17.

"The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number."

For more information, see this patent application: Frey, Matthew H.; Robrecht, Michael J.; Jambor, George F. Touch Screen Sensor. Filed February 6, 2014 and posted August 14, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5574&p=112&f=G&l=50&d=PG01&S1=20140807.PD.&OS=PD/20140807&RS=PD/20140807

Keywords for this news article include: 3m Innovative Properties Company.

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Source: Politics & Government Week


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