Method for determining active input elements of an input arrangement and input arrangement

• US 9,876,510 B2
• Filed: 02/21/2014
• Issued: 01/23/2018
• Est. Priority Date: 02/28/2013
• Status: Active Grant

• Current Assignee: Christoph Heldeis
• Original Assignee: Christoph Heldeis
• Inventors: Heldeis, Christoph, Hacke, Tilo
• Primary Examiner(s): Wilson, Brian
• Application Number:
  US14/768,121
• Publication Number:
  US 20160013806A1
• Time in Patent Office: 1,432 Days
• Field of Search: 341 24, 341 26, 341 34
• CPC Class Codes: H03M 11/003 Phantom keys detection and prevention
• CPC Class Codes: H03M 11/20 Dynamic coding, i.e. by key scanning H03M11/26 takes precedence

Abstract

The invention relates in an aspect A to a method for determining active input elements (S1a, S2a) of an input arrangement (10), comprising

• • providing input elements (S1a to S2b) that are connected according to a matrix arrangement,
  • providing within the matrix arrangement at least two drive lines (L1, L2) that are each connected to a respective driving circuit (2, 4),
  • providing within the matrix arrangement at least two sense lines (Ca, Cb) that may be used to detect active input elements (S1a, S2a),
  • providing within the matrix arrangement serial connections (SC1 to SC4) each comprising one of the input elements (S1a) and a resistor (R1a) and each serial connection (SC1 to SC4) being connected to a respective one of the drive lines (L1, L2) and to a respective one of the sense lines (Ca, Cb),
  • providing pull resistors (Ra, Rb) that connect the sense lines (Ca, Cb) to a first potential, and
  • using a control device for the driving circuits that drives an active drive line (L1) to a second potential that is different from the first potential and that drives a non active drive line (L2) or non active drive lines to the first potential or to a potential having an absolute offset value from the first potential that is at most 50 percent or at most 10 percent of the absolute value of the difference of the first potential and of the second potential.

Claims

1. A method for determining active input elements (S1a, S2a) of input elements (S1a to S2b) of an input arrangement (10), comprising:

providing the input elements (S1a to S2b) such that they are connected according to a matrix arrangement (Ma),

providing within the matrix arrangement (Ma) at least two drive lines (L1, L2) that are each connected to a respective driving circuit (2, 4),

providing within the matrix arrangement (Ma) at least two sense lines (Ca, Cb) that are used to detect the active input elements (S1a, S2a),

providing within the matrix arrangement (Ma) serial connections (SC1 to SC4) each comprising a respective input element (S1a to S2b) of the input elements (S1a to S2b) and a resistor (R1a to R2b) and each of the serial connections (SC1 to SC4) being connected to a respective one of the drive lines (L1, L2) and to a respective one of the sense lines (Ca, Cb),

providing pull resistors (Ra, Rb) that connect the sense lines (Ca, Cb) to a first potential, and

using a control device and the driving circuits (2, 4) to selectively activate by driving a first drive line (L1) of the at least two drive lines (L1, L2) to a second potential that is different from the first potential and to selectively activate by driving a second drive line (L2) or other respective drive lines of the at least two drive lines (L1, L2) to the first potential or to a potential having an absolute offset value from the first potential that is at most 50 percent of the absolute value of the difference of the first potential and of the second potential,

the method further comprising;

activating the first drive line (L1) of the at least two drive lines (L1, L2), wherein only one drive line (L1, L2) of the at least two drive lines (L1, L2) is active at one time,

detecting a first value of an electrical signal on a first sense line (Ca) of the at least two sense lines (Ca, Cb) during activating the first drive line (L1), and

determining the respective activated input element (S1a, S2a) of the input elements (S1a to S2b) in the respective serial connection (SC1, SC2) of the serial connections (SC1 to SC4) between the first drive line (L1) and the first sense line (Ca) due to an undershoot or due to exceeding of a threshold value (SW) by the first value,

whereby the threshold value (SW) is independent of a number of the active input elements (S1a, S2a) or independent of at least two, three or four different numbers of the active input elements (S1a, S2a) on the first sense line (Ca) and/or on the other sense lines (Ca, Cb) of the at least two sense lines (Ca, Cb),

wherein the matrix arrangement (Ma) comprises a calibration line (Ccc),

whereby reference resistors (R1cc, R2cc) are connected to the calibration line (Ccc) and to each of the at least two drive lines (L1, L2) respectively, and

wherein the method comprises;

detecting a calibration value using the calibration line (Ccc),

using the calibration value to determine the threshold value (SW), and

whereby the calibration line (Ccc) is connected to the first potential by a further pull resistor (Rcc).

2. The method according to claim 1, comprising:

detecting a second value of an electrical signal on a second sense line (Cb) of the at least two sense lines (Ca, Cb) during activating the first drive line (L1),

determining a respective activated input element (S1b) of the input elements (S1a to S2b) in the respective serial connection (SC3) of the serial connections (SC1 to SC4) between the first drive line (L1) and the second sense line (Cb) due to an undershoot or due an exceeding of the threshold value (SW) by the second value.

3. The method according to claim 2, comprising

deactivating the first drive line (L1) after detecting the first value and the second value,

activating the second drive line (L2) of the at least two drive lines (L1, L2),

determining a respective activated input element (S2b) in the respective serial connection (SC2) of the serial connections (SC1 to SC4) between the second drive line (L2) and the first sense line (Ca) due to an undershoot or due an exceeding of the threshold value (SW) by the first value.

4. The method according to claim 1, whereby the calibration line (Ccc) is sensed and the threshold value (SW) is determined after the activation of a respective drive line (L1, L2) of the at least two drive lines (L1, L2) but before sensing of one of the at least two sense lines (Ca, Cb).

5. The method according to claim 1, whereby the threshold value (SW) is a first threshold value (SW) that is used to calculate or to determine further threshold values or threshold ranges (TR1 to TR11) which indicate different numbers of activated input elements (S1a to S2b) on a respective sense line (Ca, Cb) of the at least two sense lines (Ca, Cb).

6. The method according to claim 1, whereby the resistors (R1a to R2b) or the resistors (R1a to R2b) and the pull resistors (Ra, Rb, Rcc) have the same resistance values, within a range of tolerance smaller than 5 percent with regard to a largest resistance value of the applicable resistors (R1a to R2b) and the applicable pull resistors (Ra, Rb, Rcc),

and/or whereby the resistors (R1a to R2b) have a fixed resistance value, or there is no pressure sensitivity of the resistors (R1a to R2b),

and/or whereby the resistors (R1a to R2b) or the resistors (R1a to R2b) and the pull resistors (Ra, Rb, Rcc) are produced by carbon printing,

and/or wherein the resistors (R1a to R2b) have resistance values of at least 4.5 kilo ohms or 5 kilo ohms.

7. The method according to claim 1, whereby a scanning of the matrix arrangement (Ma) is accelerated by at least one of the following measures:

it is determined how many respective input elements (S1a to S2b) of the input elements (S1a to S2b) are active on a respective sense line (Ca, Cb) of the at least two sense lines (Ca, Cb) as soon as the first active input element (S1a to S2b) of the input elements (S1a to S2b) is detected at the respective sense line (Ca, Cb) based on a detected value and based on threshold values (TR1 to TR11) that indicates a number of active input elements (S1a to S2b),

no further electrical signal is detected as soon as the number of respective active input elements (S1a to S2b) is detected that is equal to the indicated number of active input elements (S1a to S2b),

all drive lines (L1, L2) of the at least two drive lines (L1, L2) are driven to the second potential and respective sense lines (Ca, Cb) of the at least two sense lines (Ca, Cb) are determined that do not have respective activate input elements (S1a, S2a) of the input elements (Sa1 to S2b),

the determined respective sense lines (Ca, Cb) are not considered during the scan of the matrix arrangement (Ma) within a current scan cycle any more,

an order of driving the at least two drive lines (L1, L2) is dependent on a probability of active input elements (S1a, S2a) connected to a corresponding drive line (L1, L2) of the at least two drive lines (L1, L2),

a bisection method is used for driving the at least two drive lines (L1, L2).

8. The input arrangement (10), for performing a method according to claim 1, comprising:

the active input elements (S1a, S2a) of the input elements (S1a to S2b),

wherein the input elements (S1a to S2b) are connected according to the matrix arrangement (Ma),

wherein the matrix arrangement (Ma) comprises the at least two drive lines (L1, L2) that are each connected to a respective driving circuit (2, 4) of the driving circuits (2, 4),

wherein the matrix arrangement (Ma) comprises the at least two sense lines (Ca, Cb) that are used to detect the active input elements (S1a, S2a),

whereby, according to the matrix arrangement (Ma), the serial connections (SC1 to SC4) each comprising a respective input element (S1a to S2b) of the input elements (S1a to S2b) and the resistor (R1a to R2b) are each connected to a respective one of the at least two drive lines (L1, L2) and to a respective one of the at least two sense lines (Ca, Cb).

9. The input arrangement (10) according to claim 8, wherein the at least two sense lines (Ca, Cb) are connected to the first potential by the pull resistors (Ra, Rb), and

wherein the control device for the driving circuits (2, 4) selectively activates by driving a first drive line (L1) of the at least two drive lines (L1, L2) to the second potential that is different from the first potential and selectively activates by driving a second drive line (L2) or other respective drive lines (L1, L2) of the at least two drive lines (L1, L2) to the first potential or to the potential having the absolute offset value from the first potential that is at most 50 percent of the absolute value of the difference of the first potential and of the second potential.

10. A method for determining active input elements (S1a, S2a) of input elements (S1a to S2b) of an input arrangement (10), comprising:

providing the input elements (S1a to S2b) such that they are connected according to a matrix arrangement (Ma),

providing within the matrix arrangement (Ma) at least two drive lines (L1, L2) that are each connected to a respective driving circuit (2, 4),

providing within the matrix arrangement (Ma) at least two sense lines (Ca, Cb) that are used to detect the active input elements (S1a, S2a),

providing within the matrix arrangement (Ma) serial connections (SC1 to SC4) each comprising a respective input element (S1a to S2b) of the input elements (S1a to S2b) and a resistor (R1a to R2b) and each of the serial connections (SC1 to SC4) being connected to a respective one of the drive lines (L1, L2) and to a respective one of the sense lines (Ca, Cb),

providing pull resistors (Ra, Rb) that connect the sense lines (Ca, Cb) to a first potential, and

using a control device and the driving circuits (2, 4) to selectively activate by driving a first drive line (L1) of the at least two drive lines (L1, L2) to a second potential that is different from the first potential and to selectively activate by driving a second drive line (L2) or other respective drive lines of the at least two drive lines (L1, L2) to the first potential or to a potential having an absolute offset value from the first potential that is at most 50 percent of the absolute value of the difference of the first potential and of the second potential,

said method, further comprising;

activating one drive line (L1) of the at least two drive lines (L1, L2),

sensing a first value of an electrical signal on one sense line (Ca) of the at least two sense lines (Ca, Cb) during activating the one drive line (L1),

wherein it is tested whether the first sensed value is different from a value which indicates that no respective input element (S1a to S2b) of the input elements (S1a to S2b) is pressed on the one sense line (Ca), and

wherein a respective input element (S1a) of the input elements (S1a to S2b) between the one drive line (L1) and the one sense line (Ca) is classified as being a respective active input element (S1a) of the active input elements (S1a, S2a) if the testing is positive,

without further testing for ghost keying, including without further testing for at least one respective input element (S1a to S2b) of the input elements (S1a to S2b) configured to be detected as a respective active input element (S1a, S2a) of the active input elements (S1a to S2b) although it is not activated,

wherein a key code of the respective input element (S1a) of the input elements (S1a to S2b) that is classified as being the respective active input element (S1a) is transferred to a computer,

wherein the first potential is a positive operation potential,

wherein the matrix arrangement (Ma) comprises a calibration line (Ccc),

wherein respective reference resistors (R1cc, R2cc) are connected to the calibration line (Ccc) and to each respective drive line (L1, L2) of the at least two drive lines (L1, L2), and

wherein the calibration line (Ccc) is connected to or connectable to a detection unit for detecting a calibration value.

11. The input arrangement (10) according to claim 10, comprising a threshold determination unit that determines a threshold value (SW) that indicates a respective active input element (S1a to S2b) of the detected active input elements (S1a to S2b) independent of a number of detected active input elements (S1a to S2b) or independent of at least two or three or four different numbers of detected active input elements (S1a to S2b) connected to the same respective sense line (Ca, Cb) of the at least two sense lines (Ca, Cb) and/or that determines at least one threshold value or threshold range (TR1 to TR11) that indicates an exact number of detected active input elements (S1a to S2b) connected to the same respective sense line (Ca, Cb).

12. The input arrangement (10) according to claim 10, wherein the detection unit is operated by an operation potential and a reference potential, wherein the reference potential is filtered in a smoother way compared to the operation potential of the detection unit.

13. The input arrangement (10) according to claim 10, wherein the calibration line (Ccc) is connected to the first potential by a further pull resistor (Rcc), whereby the resistors (R1a to R2b) or the resistors (R1a to R2b) and the resistors (Ra, Rb, Rcc) have the same resistance values, within a range of tolerance smaller than 5 percent, with regard to a largest resistance value of the applicable resistors (R1a to R2b) and the applicable pull resistors (Ra, Rb, Rcc),

and/or whereby the resistors (R1a to R2b) have a fixed resistance value,

and/or whereby the resistors (R1a to R2b) or the resistors (R1a to R2b) and the pull resistors (Ra, Rb, Rcc) were produced by carbon printing,

and/or wherein the resistors (R1a to R2b) have resistance values of at least 4.5 kilo ohms or 5 kilo ohms.

14. The input arrangement (10) according to claim 10, wherein the resistor (R1a to R2b) of the serial connection (SC1 to SC4) is unmovable with regard to a carrier substrate of the matrix arrangement (Ma),

or wherein the resistor (R1a to R2b) of the serial connection (SC1 to SC4) is movable with regard to a carrier substrate of the matrix arrangement (Ma).

15. The input arrangement (10) according to claim 10, wherein there are no decoupling diodes within and/or connected to the matrix arrangement (Ma).

16. The input arrangement (10) according to claim 10, wherein a respective driving circuit (2, 4) of the driving circuits (2, 4) or the driving circuits (2, 4) for driving the at least two drive lines (L1, L2) are connected directly to the at least two drive lines (L1, L2) or by using a serial resistor (6, 8) having a resistance smaller than 200 ohms or smaller than 100 ohms,

wherein no pull resistor is used connected to an output of the respective driving circuit (2, 4) or no pull resistors are used connected to outputs of the driving circuits (2, 4).

17. The input arrangement (10) according to claim 10, wherein a respective driving circuit (2, 4) of the driving circuits (2,4) is or wherein the driving circuits (2, 4) are output circuits of a microcontroller unit (26).

18. The input arrangement (10) according to claim 10, wherein the detection unit is a first detection unit, the input arrangement (10) further comprising a second detection unit that is operated by an operation potential and a reference potential, wherein the reference potential is filtered in a smoother way compared to the operation potential of the second detection unit.