Touch screen rendering system and method of operation thereof
A touch-screen display apparatus, the apparatus may include first and second sheets having opposed major surfaces and a size and shape defined by a periphery. The periphery may be defined by opposed ends and opposed edges. The first and second sheets may each have a conductive pattern including a pair of opposed busbars and a plurality of traces electrically coupled to, and extending between, corresponding pairs of opposed busbars. The transparent force sensing (TFS) sheet may have opposed major surfaces and a variable resistance which is related to a force exerted upon one or more of its major surfaces. The TFS sheet may be situated between the first and second sheets. The apparatus may also include one or more separation portions situated between the TFS sheet and the first or second sheet to bias the TFS sheet apart from the first or second sheet.
1. A method of operating a touch panel (TP) using a controller, the method comprising:
applying a first predetermined voltage (Vcc) across a first end of a first conductive pattern having first and second ends on a first layer and a second end of a second conductive pattern electrically coupled to the first conductive pattern via a resistance (Rt), the second conductive pattern having first and second ends on a second layer;
determining a first voltage (V 1 ) at the second end of the first conductive pattern;
determining a second voltage (V 2 ) at the first end of the second conductive pattern;
applying a second predetermined voltage (Vcc 2 ) across the first and second ends of the first conductive pattern, and measuring a third voltage (V 3 ) at the second end of the second conductive pattern;
determining a value of the resistance (Rt) as a function of the first voltage (V 1 ), the second voltage (V 2 ), the third voltage (V 3 ), and a layer resistance (Rx), wherein the layer resistance (Rx) is the resistance across the first and second ends of the first conductive pattern, said function defined by the equation:
Rt =( V 2 /V 1−1)( Vx/Vcc )* Rx;
and, producing a control signal based on the determined value of the resistance (Rt).
2. The method of claim 1 , further comprising determining a magnitude of a force applied to the first or second layers of the touch panel (TP) based upon a value of the resistance (Rt).
3. The method of claim 1 , further comprising
determining a coordinate of a force applied to the first or second layers of the touch panel (TP) based upon a ratio of the third voltage (V 3 ) to the second predetermined voltage (Vcc 2 ).
4. The method of claim 1 , wherein the resistance (Rt) comprises a variable resistance across a transparent force sensing (TFS) sheet interposed between the first and second layers.
5. A non-transitory computer program stored on a computer readable persistent memory medium, the computer program configured to operate a touch panel (TP) of a user interface (UI), the computer program comprising:
a program portion controlling a processor to:
apply a first predetermined voltage (Vcc) across a first end of a first conductive pattern having first and second ends on a first layer and a second end of a second conductive pattern electrically coupled to the first conductive pattern via a resistance (Rt), the second conductive pattern having first and second ends on a second layer;
determine a first voltage (V 1 ) at the second end of the first conductive pattern;
determine a second voltage (V 2 ) at the first end of the second conductive pattern;
apply a second predetermined voltage (Vcc 2 ) across the first and second ends of the first conductive pattern, and measure a third voltage (V 3 ) at the second end of the second conductive pattern;
determine a value of the resistance (Rt) as a function of the first voltage (V 1 ), the second voltage (V 2 ), the third voltage (V 3 ), and a layer resistance (Rx), wherein the layer resistance (Rx) is the resistance across the first and second ends of the first conductive pattern, said function defined by the equation:
Rt =( V 2 /V 1−1)( Vx/Vcc )* Rx;
and produce a control signal based on the determined value of the resistance (Rt).
6. The computer program of claim 5 , wherein the program portion is configured to:
determine a magnitude of a force applied to the first or second layers of the touch panel (TP) based upon a value of the resistance (Rt); and
determine a coordinate of the force based upon a ratio of the third voltage (V 3 ) to the second predetermined voltage (Vcc 2 ).
7. The method of claim 1 , wherein the first predetermined voltage (Vcc) and the second predetermined voltage (Vcc 2 ) are equal.
8. The computer program of claim 5 , wherein the first predetermined voltage (Vcc) and the second predetermined voltage (Vcc 2 ) are equal.