Patent Application
20090044640
The invention relates to an electronic pen comprising a lead equipped with a tip and an ink container, and detection means associated with the lead comprising a force sensor designed to measure the forces applied on the lead by the user.
Electronic stylus pens are conventionally designed to digitize writing and to capture graphic gestures. To achieve this objective, current electronic pens, in particular the electronic pen described in U.S. Pat. No. 4,751,741, use measurement of the forces applied on the lead by the user. In addition, they are generally equipped with a standard cylindrical-shaped ink cartridge with a length of about 50 mm to 100 mm. The ink cartridge is equipped with several force sensors placed on the body thereof in three orthogonal directions of a reference frame.
Electronic pens of this kind present several shortcomings. The cartridge is relatively long and the force sensors are placed far from the tip of the lead, which can lead to measurements that are not representative of the force applied on the lead. The force sensors are numerous, which can give rise to problems of space occupation inside the pen. The sensors are placed on the body of the cartridge, which can result in handling problems and damage when changing the cartridge.
The object of the invention is to remedy the above-mentioned shortcomings and has the object of providing a high-performance electronic pen enabling writing to be performed using precise and reliable measurements of the forces applied on its lead.
The object of the invention is characterized in that the force sensor is a three-dimensional force sensor comprising a sensitive detection element placed in the axis of the tip of the lead, and that the pen comprises at least a first element made of flexible material arranged between the ink container and the three-dimensional force sensor.
Other advantages and features will become more clearly apparent from the following description of particular embodiments of the invention given as non-restrictive examples only and represented in the accompanying drawings, in which:
In the figures, an electronic pen 1 is particularly designed for writing and for measuring the forces applied on its lead. Electronic pen 1 comprises a lead 2 equipped with a tip 3, securedly fixed to an ink container 4 partially housed inside a lead body 5, which is for example substantially tubular-shaped. Ink container 4 comprises a preferably substantially conical-shaped upper part 4a equipped at its end with tip 3 and salient from lead body 5 to form the free end of electronic pen 1. Ink container 4 delineates a cavity wherein the ink is stored, tip 3 passing through substantially conical-shaped upper part 4a to be in contact with the ink contained in ink container 4.
Pen 1 comprises a three-dimensional force sensor 6 designed to detect all the forces applied by the user on lead 2. Force sensor 6 in particular comprises a sensitive detection element 7, that is for example substantially cylindrical-shaped, placed at the level of an axis of symmetry 8 of electronic pen 1. Sensitive element 7 is designed to detect all the forces exerted on lead 2 of the pen in the three orthogonal directions of the reference system relative to electronic pen 1.
Moreover, three-dimensional force sensor 6 is supported by a support 9 arranged perpendicularly to axis of symmetry 8 of pen 1, inside lead body 5.
In the particular embodiment of
For example, first flexible material element 10 is made of polyurethane with a stiffness of less than 10 MPa. First element 10 can preferably be produced by machining a block of polyurethane or by molding. The stiffness of first flexible material element 10 is chosen such that first flexible material element 10 protects three-dimensional force sensor 6, while transmitting the forces correctly.
In
Moreover, ink container 4 does not completely fill the inside of lead body 5. Second flexible material element 11 comprises a salient part 11a, shaped as an annular crown of small thickness, surrounding ink container 4 inside lead body 5. Second flexible material element 11 therefore acts mainly as support element for ink container 4 inside lead body 5.
For example, second flexible material element 11 is made of foam with a stiffness of about 0.1 MPa. The stiffness of second element 11 is particularly chosen such that ink container 4 equipped with tip 3 is held without clearance inside lead body 5.
In the particular embodiment represented in
Third flexible material element 12 is therefore adjacent both to first flexible material element 10, to second flexible material element 11, to the edges of three-dimensional force sensor 6 and to support 9 of three-dimensional force sensor 6. Third flexible material element 12 is particularly designed to reduce the overall stiffness of electronic pen 1. For example, third flexible material element 12 is made of silicone glue with a stiffness of about 1 MPa.
In
For example, for a radius R of lead body 5 of about 7 mm, the height H1 of ink container 4 is about 5 mm, with a volume of more than 500 mm3, and three-dimensional force sensor 6 is situated at a distance H2 of less than 15 mm is with respect to the end of tip 3 of lead 2. Three-dimensional force sensor 6 is preferably achieved by means of microtechnology techniques.
In the alternative embodiment represented in
Electronic pen 1 always comprises three-dimensional force sensor 6 positioned along the axis 8 of pen 1 and a first element 15 made of flexible material arranged between ink container 4 and three-dimensional force sensor 6. In the particular embodiment of
As before, first flexible material element 15 is designed to transmit the forces applied on lead 2 to three-dimensional force sensor 6. For example, first flexible material element 15 is made of polyurethane with a stiffness of less than 10 MPa and can be produced by machining a block of polyurethane or by molding. The stiffness of first flexible material element 15 is chosen such that first flexible material element 15 protects three-dimensional force sensor 6, while transmitting the forces correctly.
Electronic pen 1 also comprises a second element 17 made of flexible material surrounding ink container 4 inside lead body 5. Second flexible material element 17, shaped as an annular crown of small thickness, is designed to secure the fixed part of ink container 4 inside lead body 5.
As before, second flexible material element 17 is for example made of foam with a stiffness of about 0.1 MPa. The stiffness of second element 17 is particularly chosen in such a way that ink container 4 is held without any clearance inside lead body 5.
Moreover, first flexible material element 15 and second flexible material element 17 delineate a cavity 18 inside lead body 5 in particular enabling first flexible material element 15 to deform freely when pen 1 is used. This results in optimal transmission of the forces to three-dimensional force sensor 6.
As before, for a radius R of lead body 5 of about 7 mm, the height H1 of ink container 4 is about 5 mm, with a volume of more than 500 mm3, and three-dimensional force sensor 6 is situated at a distance H2 of less than 15 mm from the end of tip 3 of lead 2.
Whatever the embodiment of electronic pen 1, the latter enables very reliable and very precise measurements to be made, in particular on account of the positioning of three-dimensional force sensor 6 very close to tip 3 of lead 2 and exactly in the axis 8 of the latter. Furthermore, the space occupied inside pen 1 is minimal due to the use of a single three-dimensional force sensor 6, preferably achieved by means of microtechnology techniques.
Furthermore, as three-dimensional force sensor 6 is independent from ink container 4 of pen 1, ink container 4 can be changed and refilled without touching three-dimensional force sensor 6. Refilling of ink container 4 is therefore simplified and handling of electronic pen 1 is made easier, in particular due to removable top part 4a of ink container 4 (
The invention is not limited to the different embodiments described above. It is possible to use any type of three-dimensional force sensor 6. Flexible material elements 10, 11, 12, 15, 17 can be formed by any other flexible material and can have a quite different shape provided that they enable three-dimensional force sensor 6 and ink container 4 to be secured inside lead body 5 and the forces to be transmitted between tip 3 of lead 2 and three-dimensional force sensor 6.
Furthermore, the height H1 of ink container 4, the height H2 between three-dimensional force sensor 6 and the end of tip 3 and the radius R of lead body 5 are non-restrictive dimensions and depend in practice on the general size of the electronic pen 1 involved.
Such an electronic pen 1 is used particularly to determine the trajectory of lead 2 of pen 1 in the plane of a sheet, by means of electronic retranscription functions, and to characterize, authenticate and/or recognize a signature.
| Number | Date | Country | Kind |
|---|---|---|---|
| 05 07467 | Jul 2005 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR2006/001624 | 7/6/2006 | WO | 00 | 12/19/2007 |
