Device for locating the unknown position of an electrical conductor belonging to a set of separate conductors and a touch sensitive panel comprising such devices

• US 4,990,725 A
• Filed: 06/19/1989
• Issued: 02/05/1991
• Est. Priority Date: 07/13/1988
• Status: Expired due to Term

• Current Assignee: Tactil Group Limited
• Original Assignee: AID 3 Group, Ltd.
• Inventors: Mizzi, Francois
• Primary Examiner(s): Schreyer, Stafford D.
• Application Number:
  US07/367,687
• Time in Patent Office: 596 Days
• Field of Search: 178/79, 178/18, 178/19, 178/20
• US Class Current: 178/18.05
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position

Abstract

The device locates the position x of the point of connection of one of the electric conductors (2) of unknown ohmic values, connected to unknown separate points of a collecting resistor (R₁) of unknown but constant ohmic value per unit length, to which a standard resistor (R_e) is also connected whose ohmic value is a known optimal multiple (k) of that of R₁. The superposition of two such devices, separated by small rods of elongated form, may serve to create a dependable and inexpensive opaque or transparent panel allowing the locating of the position (x, y) of the one of its points as soon as a slight pressure is exerted on this point.

Claims

1. A device for locating the unknown position of a specific electrical conductor belonging to a set of separate conductors of any indeterminate resistivities, in which at least a first point of each conductor is connected to separate points of a first collecting resistor of constant ohmic value per unit length, said device comprising:

(a) a standard resistor connected at one of its ends to a point of the collecting resistor,

(b) first means for determining the value of the potential difference appearing both between the ends of the collecting resistor and between those of the standard resistor when the said electrical conductor and the second end of the said standard resistor are brought to respective potentials of different value from one another,

(c) other means for determining the value of the distance separating the said conductor of unknown position and an origin point, predefined on the collecting resistor, on the one hand as a function of a constant characteristic of the value of the standard resistor and of the specific resistance per unit length of the collecting resistor, and on the other hand, from the values of the potential differences determined by said first means.

2. A device according to claim 1, the separate conductors being connected individually at a second point to corresponding separate points of a second collecting resistor of identical structure to that of the first collecting resistor, and said standard resistor being connected at one of its ends to a corresponding points of each collecting resistor, and including electric connections of negligible resistive value compared with the value of the said resistors connecting the corresponding ends of the collecting resistors.

3. A device according to claim 1, said standard resistor being connected to one of the ends of the collecting resistor.

4. A device according to claim 1, said standard resistor being connected at the mid-length of the collecting resistor.

5. A device according to claim 1, said separate conductors being carried by a common substrate, and said collecting and standard resistors being each comprised of a resistive ohmic coating formed on the substrate and each having a constant and identical specific resistivity per unit length.

6. A device according to claim 5, said standard resistor being at least equal to 0.20 times that of the collecting resistor.

7. A device according to claim 5, said standard resistor being at least equal to 0.10 times that of the collecting resistor.

8. A device for locating the unknown position of a specific electrical conductor belonging to a first set of separate conductors of indeterminate resistivities, in which at least a first point of each conductor of said first set of separate conductors is connected to a respective separate point on a first collecting resistor of constant ohmic value per unit length, the device comprising

(a) a standard resistor being formed by at least a part of the length of a resistor of identical structure to that of the first collecting resistor and extending at a spacing from the first collecting resistor, near to the second ends of the separate conductors associated with the first collecting resistor,

(b) a second set of separate conductors, each of which extends between two conductors of the first set of conductors, near to these, the conductors of the second set being connected individually to separate points of said standard resistor,

(c) first means for determining the value of the potential difference appearing between the ends of the first collecting resistor and that appearing between the ends of the standard resistor when one of the ends of the first collecting resistor and the opposite end of the standard resistor are brought to respective reference potentials of different value from resistor to resistor, and an electrical contact being established between the conductor of unknown position of the first set of conductors and an adjacent conductor belonging to the second set of conductors, and

(d) other means for determining the value of the distance separating the position of the electrical contact from an origin point, predefined on the first collecting resistor, on the one hand as a function of a constant characteristic of the value of the standard resistor and of the specific resistance per unit length of the collecting resistor, and on the other hand, from the values of the potential differences determined by said first means.

9. A touch sensitive panel for the entry of information, comprising:

a first device for locating the unknown position of a specific electrical conductor belonging to a first set of separate conductors of indeterminate resistivities, in which at least a first point of each conductor of said first set of separate conductors is connected to a respective separate point on a first collecting resistor of constant ohmic value per unit length, said first device including;

(a) a standard resistor having an end connected to a point on the first collecting resistor,

(b) first means for determining the value of the potential difference appearing between the ends of the first collecting resistor and that appearing between the ends of the first standard resistor when said specific electrical conductor and a second end of said standard resistor are brought to respective potentials of different value from one another, and

(c) second means for determining the value of the distance separating said specific conductor of unknown position from an origin point, predefined on the first collecting resistor, on the one hand as a function of a constant characteristic of the value of the standard resistor and of the specific resistance per unit length of the first collecting resistor, and on the other hand, from the values of the potential differences determined by said first means

a second device for locating the unknown position of a specific electrical conductor belonging to a second set of separate conductors of indeterminate resistivities, in which at least a first point of each conductor of said second set of separate conductors is connected to a respective separate point on a second collecting resistor of constant ohmic value per unit length, said second device including;

(d) a standard resistor having an end connected to a point on the second collecting resistor,

(e) third means for determining the value of the potential difference appearing between the ends of the second collecting resistor and that appearing between the ends of the standard resistor when said specific electrical conductor and a second end of said standard resistor are brought to respective potentials of different value from one another, and

(f) fourth means for determining the value of the distance separating said specific conductor of unknown position from an origin point, predefined on the second collecting resistor, on the one hand as a function of a constant characteristic of the value of the standard resistor and of the specific resistance per unit length of the second collecting resistor, and on the other hand, from the values of the potential differences determined by said third means

said first and second devices being carried by an individual substrate for each device, at least one of the substrates being of a flexible and elastic material, the substrates being superpositioned and disposed in such a way that the conductors of each substrate form a group crossing at a spacing the conductors of the other group belonging to the second substrate, each conductor of a group crossing over once and only once all of the conductors of the other group, spacing elements of the substrates maintaining the conductors of each substrate spaced from those of the other substrate in a rest position of the substrate of flexible material, each conductor of this substrate being capable of being brought into contact with at least one conductor of the other substrate by elastic deformation of the flexible substrate caused by a localized pressure exerted on this in the desired region for contact.

10. A panel according to claim 9, said spacing elements being formed by individual rods of one and/or the other substrate, their longitudinal axis being oriented parallel to the conductors of at least one of the devices and the thickness of these rods being less than or equal to their width, itself less than or equal to their length.

11. A panel according to claim 9, comprising a standard resistor common to said first and second devices, this resistor being connected to a point of the collecting resistor of one of said first and second devices.

12. A panel according to claim 11, said standard resistor being connected in series with said collecting resistor.

13. A panel according to claim 12, said ohmic value of the standard resistor being substantially equal to 1/4 of the sum of the ohmic values of the collecting resistors of said first and second devices.

14. A panel according to claim 11, said standard resistor of each of said first and second devices being formed by the collecting resistor of the other of said first and second devices.