Data entry stylus

1. A stylus for entering data on to an entry pad, said stylus comprising:

a body comprising a housing;

a reference element comprising two distinct portions:

a first portion seated within said housing; and

a second portion comprising a tip, the tip having a bottom end that is at least hemispherical, a reference point in a center of the bottom end of the second portion being used to evaluate a distance d between the reference point and the entry pad;

a damper forming a cladding around at least one part of said reference element, comprising an external wall, called an external wall of said damper, which acts as a variator of the distance d between the reference point and the entry pad in response to a change in pressure exerted on the stylus.

2. The stylus according to claim 1 , wherein said damper is made out of a flexible and deformable material.

3. The stylus according to claim 1 , wherein said damper is hemispherical.

4. The stylus according to claim 1 , wherein said bottom end is substantially spherical.

5. The stylus according to claim 1 , wherein said damper comprises a cylindrical sleeve comprising a first hemispherical end, the internal diameter of the cylindrical sleeve being substantially equal to the diameter of the at least hemispherical bottom end of the second portion of the reference element.

6. The stylus according to claim 5 , wherein said damper furthermore comprises a second end comprising a retaining ring for retaining said damper in said housing.

7. The stylus according to claim 5 , wherein a space left vacant between said first hemispherical end and the at least hemispherical bottom end of the reference element is filled with an electrically charged deformable material.

8. The stylus according to claim 5 , wherein said damper is mobile in translation according to pressure exerted on the stylus.

9. A method for measuring a pressure exerted during the entry of data by a user, entered on a writing surface of a pad via a stylus, the stylus comprising a reference element comprising two distinct portions:

a first portion seated within a housing; and

a second portion comprising a tip, the tip having a bottom end that is at least hemispherical, a reference point in a center of the bottom end of the second portion being used to evaluate a distance d between the reference point and the pad,

wherein the method comprises:

acquisition, by said writing surface, at at least one instant of the entry, of at least one piece of data representing the distance d of the reference point of said stylus relative to said pad, in a zone of proximity of said pad; and

computing pressure exerted on said pad taking account of said distance d.

10. A non-transitory computer-readable memory comprising a computer program product stored thereon, which comprises program code instructions for executing a method for measuring a pressure exerted during the entry of data by a user, entered on a writing surface of a pad via a stylus, when the instructions are executed on a computer, wherein the stylus comprises a reference element comprising two distinct portions:

a first portion seated within a housing; and

a second portion comprising a tip, the tip having a bottom end that is at least hemispherical, a reference point in a center of the bottom end of the second portion being used to evaluate a distance d between the reference point and the pad, and

wherein the method comprises:

acquisition, by said writing surface, at at least one instant of the entry, of at least one piece of data representing the distance d of the reference point of said stylus relative to said pad, in a zone of proximity of said pad; and

computing pressure exerted on said pad taking account of said distance d.