WO2008065205A1

WO2008065205A1 - Data entry device and method for implementing the device

Info

Publication number: WO2008065205A1
Application number: PCT/EP2007/063177
Authority: WO
Inventors: Pierre Fagard; Philippe Coni
Original assignee: Thales
Priority date: 2006-12-01
Filing date: 2007-12-03
Publication date: 2008-06-05
Also published as: FR2909464B1; FR2909464A1

Abstract

The invention relates to a data entry device and a method for implementing the device. The device comprises a sensitive module (2), means for detecting proximity of an operator (3) in relation to the sensitive module (2), wherein the proximity detection means can generate a first signal according to the proximity of the operator (3), and means for detecting a pressure exerted by the operator (3) on the sensitive module (2), wherein the pressure detection means can generate a second signal according to the pressure of the operator (3). According to the invention, the proximity detection means (6) and the pressure detection means (16, 17) are separate and the device further comprises a common processing chain (27) for the signals transmitted and received by the proximity detection means and by the pressure measuring means. According to the method, the proximity of the operator (3) in relation to the sensitive module (2) and the pressure by the operator (3) on the sensitive module (2) is measured cyclically.

Description

Data input device and method of implementing the device

The invention relates to a data input device and a method for implementing the device. Such devices are used in particular for the production of communication terminals of the type enabling an operator to transmit information to a processor. The invention finds particular application for a screen having a touch surface on which a user can put the finger to enter data. The screen is for example liquid crystal, plasma, light emitting diodes or emission by field effect.

It is known to make such screens by placing on the device one or more transparent tactile contact pads or capacitive effect, inductive or equivalent. The device can then be used to delimit support zones of this range according to a desired composition. Beach support is usually done by an operator's finger. However, intense electromagnetic disturbances can sometimes alter the operation of the touch pads by causing false detections.

To overcome this defect, a tactile force sensor has been joined to the touch pads to detect a support of the operator's finger on the touch pad. Such an embodiment is for example described in European Patent EP 561 669. This patent describes the use of strain gauges to measure a force on the touch pad. Such an implementation poses several problems of implementation. First of all, the mechanical design is complicated by the mounting of the bearing zone on flexible blades on which the strain gauges are fixed. Then, the processing of the information from the touch pads and the strain gauges is of a different nature. For example, a capacitance variation must be measured to detect contact with the touch pad and a variation of resistance of the strain gauge to detect an effort of the operator on the touch pad.

The aim of the invention is to overcome the drawbacks of the devices described above by proposing a data input device that achieves in a simple manner both a proximity detection and a force detection. For this purpose, the subject of the invention is a data input device comprising a sensitive module, proximity detection means of an operator with respect to the sensitive module, the proximity detection means making it possible to produce a first sensor. signal depending on the proximity of the operator, and means for detecting a force exerted by the operator on the sensitive module, the force detection means making it possible to produce a second signal which is a function of the force of the operator. operator, characterized in that the proximity detection means and the force detection means are distinct and in that the device also comprises a common processing chain of the signals transmitted and received by the proximity detection means. and by the means for measuring an effort.

The fact of using the same common processing chain for proximity detection and effort detection makes it possible to reduce the costs of producing the device. The fact that the proximity detection means and the means of detecting a force are distinct allows a measurement of the effort independent of the proximity detection.

The subject of the invention is also a method for implementing the device according to the invention, characterized in that it cyclically measures the proximity of the operator with respect to the sensitive module and the effort of the operator on the module. sensitive.

The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the attached drawing in which:

Figure 1 shows schematically a device according to the invention; FIGS. 2a and 2b represent in the form of a timing diagram an example of a signal received by an analysis system common to the proximity detection means and to the force detection means; FIG. 3 represents a tactile display device embodying the invention; FIG. 4 represents a capacitive touch-screen device embodying the invention; For the sake of clarity, the same elements will bear the same references in the different figures.

FIG. 1 represents a data input device 1 comprising a sensitive module 2, for example a keyboard, proximity detection means of an operator 3 with respect to the sensitive module 2 and means for detecting a force exerted by the operator 3 on the sensitive module 2. The operator 3 is here represented by his finger.

Advantageously, the proximity detection means comprise at least a first capacitor 4 whose value is modified by the proximity of the operator 3, and the means for detecting a force comprise at least a second capacitor 5 whose value is modified. by the effort of the operator 3 operated on the sensitive module 2. The first and the second capacity are distinct. The fact that the two capacitors 4 and 5 are distinct makes it possible to dispense with the conductivity of the operator 3.

Advantageously, the first capacitor 4 comprises a first electrode 6 and an insulator 7 both integral with the sensitive module 2. The insulator 7 covers the electrode 6. A conductive part of the operator 3, such as its finger, forms a second electrode of the first capacitor 4, the conductive portion of the operator 3 being intended to come into contact with the insulator 7 facing the first electrode 6. The value of the capacitor 4 is proportional to the distance between the electrode 6 and the operator 3 for a given electrode surface (6 and / or operator 3). In FIG. 1, three electrodes 6 have been represented. The number of electrodes may vary according to the number of keys that the device 1 comprises.

The device 1 comprises a high frequency generator 10 producing a sinusoidal preference signal whose frequency is for example between 100 kHz and 5 MHz.

The high frequency signal is supplied to a multiplexer 11 responsible for sequentially distributing, under the control of a processor 12, such as for example a microcontroller, the high frequency signal on the electrodes 6. The operator 3 can be considered as connected to a reference potential with respect to a mass 13 of the device 1. The proximity detection of the operator 3 is done by measuring the attenuation of the high frequency signal due to the variation of the value of the capacitor 4. The sensitive module 2 is mounted loosely in a frame 14 and elastic elements 15 allow a slight depression of the sensitive module 2 in the frame 14 under the effect of the force exerted by the operator 3 on the sensitive module 2. Advantageously, the second capacitor 5 comprises two facing electrodes 16 and 17. The electrode 16 is integral with the sensitive module 2 and the electrode 17 is integral with the frame 14. The force on the sensitive module 2 modifies the distance separating the two electrodes 16 and 17 of the capacitance 5 as a function of the stiffness of the elastic elements 15. The high frequency signal is distributed to the electrode 16 via the multiplexer 1 1. The electrode 17 is connected to the ground 13 of the device 1. It is also possible to connect the electrode 16 to the ground 13 and the electrode 17 to the multiplexer 11. The two electrodes 16 and 17 are separated by an insulator 18 formed, for example, by air or by a suitable material covering a surface. at least one of the two electrodes 16 or 17. The effort detection of the operator 3 on the sensitive module 2 is done by measuring the attenuation of the high frequency signal due to the variation of the value of the capacitance 5. This variation in value is due to the change in distance between the two electrodes 16 and 17 under the effect of the effort of the operator 3. The high frequency signal, distributed on the electrodes 6 and 16 by the multiplexer 11, is provided by the generator 10 through an injection capacity 20, thus creating a capacitive divider consisting of the injection capacity 20 on the one hand, and in turn capacitances of electrodes and in particular capacitors 4 and 5. The voltage present at the midpoint of the capacitive divider is taken from point 21. This voltage is representative of the ratio between the injection capacity 20 and one of the capacitors 4 or 5 supplied by the multiplexer 11 at a given instant.

The voltages present at point 21 are applied to a common analysis line 22 of the signals received from the proximity detection means and the means for measuring a force. The analysis chain 22 comprises, for example, a link capacitor 23, a shaping amplifier 24, an amplitude demodulator 25 delivering a demodulated signal to an analog digital converter that can be integrated into the microcontroller 12. In other words, the chain Analysis 22 detects modifications of an electrical signal, here the high frequency signal, induced by the presence and / or the effort of the operator 3 on the sensitive module 2.

The microcontroller 12, having acquired the different electrode voltage values 6 and 16, then proceeds, by a suitable calculation algorithm, to the determination of the presence of the operator 3 and to the measurement of the force exerted by the operator 3 by measuring the variations between a state of rest (operator 3 absent) and an active state (operator 3 present), both for the electrodes 6 and for the electrodes 16.

A processing chain 27 common to the proximity detection means and the means for detecting a force is defined. The common processing chain comprises the analysis chain 22 as well as common means for distributing the electrical signal, here high frequency, to the electrodes 6 and 16. The common means for distributing the high frequency signal comprise the high frequency generator 10, the injection capacity 20 and the multiplexer 11.

Advantageously, the device comprises a third test capacitor 29 connected to the processing chain 27 and independent of the proximity detection means and the means for detecting a force. The test capacitance 29 is also addressed in sequence by the multiplexer 11, the voltage measured across the capacitor 29 enabling the microcontroller 12 to perform tests of proper operation and automatic calibration of the processing chain 27.

In Figure 1, a single capacitor 5 has been shown. It is of course possible to produce several pairs of electrodes 16 and 17. For example, for a rectangular-shaped sensitive module 2, a pair of electrodes 16 and 17 can be arranged at each corner of the rectangle to form four capacitors 5 that it can be treated separately or as a single distributed capacity. In other words, the capacitance 5 can be formed by several pairs of electrodes in parallel.

FIGS. 2a and 2b represent in chronogram form an example of voltage received by a measurement chain 22. The voltages are represented after demodulation at the output of the demodulator 25. The high frequency signal is applied sequentially to three keys t1, t2 and t3 forming each of the capacitances 4, then to the test capacitance 29 and finally to the capacity 5 of effort measurement.

FIG. 2a represents the voltages measured at rest, ie in the absence of operator 3 and FIG. 2b represents the same voltages but in the presence of an operator 3 actuating the key t2. The action of the operator 3 modifies the values of the capacitance 4 of the key t2 and of the capacitor 5. In FIG. 2b, the idle voltage values are reported in broken lines and the voltage values when the key t2 is operated are shown in bold line. The capacitance variations are translated after formatting and demodulation by a variation ΔV2 on the electrode 6 of the key t2 and ΔVF1 or ΔVF2 for the capacitor 5 allowing the measurement of effort.

Advantageously, the values in the absence of operator 3 of the capacities 5 and 6 are of the same order of magnitude. By the same order of magnitude, for example, it is meant that the values of the capacitors are in a maximum ratio of 1 to 10. When the test capacitance 29 exists, its value is advantageously also in the same order of magnitude. This ensures a good sensitivity of the analysis chain 22 without the risk of saturation. Similarly, the variation levels of the different measured capacitances, ΔV2 for the key t2 and ΔVF1 or ΔVF2 for the capacitor 5 in the example shown, also have levels of the same order of magnitude when the operator is supported. For example, it is possible to adjust the value at rest and the value under force of the capacitor 5 by adapting the dimensions of the electrodes 16 and 17 as well as the spacing at rest and under stress between the two electrodes 16 and 17.

FIG. 3 describes a display device comprising a display 30 comprising a layer 31 of material having electro-optical properties able to make all or part of its surface visible under the effect of an electrical excitation signal, at least a first electrode 33 disposed on a first face of the layer, a second electrode 32 disposed on a second face of the layer 31 opposite the first electrode 33 of the display 30. The excitation signal is applied between the electrodes 32 and 33 of the display 30. The electrodes 32 and 33 are made on transparent plates, respectively 34 and 35, for example in glass. The electrode 33 forms the electrode 6 of the capacitor 4. The use of one of the display electrodes as presence detection electrode makes it possible to produce a display device associated with a proximity detection at low cost. The excitation signal, generally low frequency, is mixed with the high frequency signal enabling proximity detection on the electrode 33. An embodiment of such a display is described in the patent application EP 1 565 806.

The display device comprises a lighting module 36 integral with the display 30, a flexible seal 37 placed between the frame 14 and the display 30, a printed circuit 38 integral with the frame 14 and on which are arranged at least the components of the processing chain 27 as well as those necessary for controlling the display 30. The lighting module 36 comprises for example light emitting diodes placed under a diffuser and for illuminating the display 30. Advantageously, the printed circuit 38 is arranged under the lighting module 36. On the printed circuit 38, the electrodes 17 in the form of metallization and the electrodes 16 are located under the lighting module 36. This arrangement allows the values of the capacitors 4 and 5 to move in the same direction during the action of the operator 3. In this case, the effort made by the operator 3 reduces the distance separating the two electrodes 16 and 17. The elastic elements 15, s Or form springs, can be placed between the lighting module 36 and the printed circuit 38. Alternatively, one can use the flexible seal 37 as an elastic element. It is possible to provide stops to limit the travel of the lighting module 36 with respect to the printed circuit 38 and more generally to limit the travel between the supports of the electrodes 16 and 17. Advantageously, a suitable insulating coating is placed on the electrodes 16 and 17.

Advantageously, the lighting module 36 comprises a shell 40 metal or metallized externally, at least in part, and connected to an electrical potential present on the printed circuit 38, for example by means of the springs 15. The metal shell or its metallized coating form then the electrode 16. The potential of the moving electrode 16 can be the electric mass 13 of the treatment chain 27 or the potential of the point 21. The lighting module 36 can be replaced by a metal reflector forming the 16. In this embodiment, the effort of the operator 3 reduces the distance between the two electrodes 16 and 17. In this arrangement the capacitors 4 and 5 vary in the same direction under the support of the operator 3. The voltage variation is represented ΔVF1 in Figure 2b for the capacitor 5. This makes it possible to reduce the range of excursion of the output voltage of the demodulator 25 or, if the same domain is retained, to increase the gain to improve the sensitivity to the low forces of the operator 3 or the sensitivity to small displacements sensitive module 2.

If it is desired another arrangement of the printed circuit 38 that would prevent placing an electrode for the detection of effort, it is advantageous to place the electrode 16 on one of the plates 34 or 35 facing a rim 39 of the frame 14. The flange 39 is electrically conductive and connected to a reference potential such as the ground 13. The flange 39 then forms the electrode 17 for the effort detection. In this case, the force exerted by the operator 3 increases the distance separating the two electrodes 16 and 17. Advantageously, the electrode 16 and the electrodes 6 are made on the same substrate, for example the plate 35. realization of the device by allowing the realization of the electrodes 6 and 16 with the same mask. In this embodiment, the effort of the operator 3 increases the distance separating the two electrodes 16 and 17. In this arrangement the capacitors 4 and 5 vary in opposite directions under the support of the operator 3. The variation of Voltage is shown ΔVF2 in Figure 2b for the capacitor 5. This provides the device 1 greater robustness to disturbances due to the variation in the opposite direction of the voltages recorded on the capacitors 4 and 5 after demodulation.

FIG. 4 describes a capacitive touch-screen device comprising a substrate 40 on which electrodes 6 are arranged for cooperating with the finger of the operator 3 to detect its proximity. An insulator 41 may cover the substrate 40 and the electrodes 6. An electrode 16 is also disposed on the substrate 40 facing the electrically conductive flange 39. Here too, the same mask makes it possible to produce the electrodes 6 and 16 on the substrate 40.

The electrodes 16 and 17 are separated by an insulator 42, constituted by air or a gasket similar to the gasket 37 and whose thickness varies according to the force exerted on the slab by the operator 3. An elastic element 15 allows a degree of freedom of the slab with a stop 43 integral with the frame 14.

A connecting circuit 44 electrically connects the electrodes 6 and 16 to the processing line 27 and more precisely to the multiplexer 11.

One can have a display 45 behind the touch screen to be seen by the operator 3.

Claims

1. Data input device comprising a sensitive module (2), proximity detection means of an operator (3) relative to the sensitive module (2), the proximity detection means for developing a first signal depending on the proximity of the operator (3), and

Means for detecting a force exerted by the operator (3) on the sensitive module (2), the force detection means making it possible to produce a second signal which is a function of the effort of the operator (3) , characterized in that the proximity detection means (6) and the force detection means (16, 17) are distinct and in that the device further comprises a common signal processing chain (27). transmitted and received by the proximity detection means and the measuring means of a force.

2. Device according to claim 1, characterized in that the processing chain transmits the same signal to the detection means of

5 proximity (6) and towards the means for measuring a force (16, 17).

3. Device according to claim 2, characterized in that the signal is transmitted sequentially to the proximity detection means (6) and to the means for measuring a force (16, 17).

0

4. Device according to one of the preceding claims, characterized in that the proximity detection means comprise at least a first capacitor (4) whose value is modified by the proximity of the operator (3), in that the means for detecting an effort include

At least a second capacity (5) whose value is modified by the effort of the operator (3) and in that the first and second capacitors (4, 5) are distinct.

5. Device according to claim 4, characterized in that the o first and second capacitances (4, 5) both have an electrode (6, 16) placed on one face of the same substrate (7) without these two electrodes. are common and in that the processing line (27) has common connection means to the substrate.

RECTDREE FURNACE (FLEGLE 91)

DSA / EP 10

6. Device according to any one of claims 4 or 5, characterized in that the sensitive module (2) comprises a display (30) comprising a layer (31) of material having electro-optical properties able to make visible all or part of its surface under the effect of an electrical excitation signal, at least a first electrode (33) disposed on a first face of the layer (31), a second electrode (32) disposed on a second face of the layer (31) opposite the first electrode (33) of the display (30), in that the excitation signal is applied between the electrodes (32, 33) of the display (30) and in that the first electrode (33) of the display (30) forms a first electrode (6) of the first capacitor (4), a conductive part of the operator (3), such as a finger of the operator (3). ), forming a second electrode of the first capacitor (4).

7. Device according to any one of claims 4 to 6, characterized in that the first capacitor (4) comprises a first electrode (6) integral with the sensitive module (2), in that the second capacitor (5) comprises a first electrode (16) integral with the sensitive module (2) and in that the first two electrodes (6, 16) are formed on the same substrate (35, 40).

8. Device according to any one of claims 4 to 7, characterized in that the device comprises a fixed frame (14), in that the sensitive module (2) is connected to the frame (14) by elastic means (15). , 37), in that the second capacitor (5) has two facing electrodes (16, 17), one (16) of which is secured to the sensitive module (2) and the other (17) of which is secured to the frame ( 14) and in that the force on the sensitive module (2) modifies the distance separating the two electrodes (16, 17) of the second capacitor (5).

9. Device according to claim 8, characterized in that the force increases the distance separating the two electrodes (16, 17) of the second capacitor (5).

RECTIFIED FEUSLLE (RULE 91)

ISA / EP 11

10. Device according to claim 8, characterized in that the force reduces the distance separating the two electrodes (16, 17) of the second capacitor (5).

11. Device according to any one of claims 4 to 10, characterized in that the values in the absence of operator (3) of the first capacity (4), the second capacity (5) are of the same order of magnitude.

12 Device according to any one of claims 4 to 11, characterized in that it comprises a third test capacitor (29) connected to the processing chain (27) and independent of the proximity detection means (6) and the means for detecting a force (16, 17) and in that the values in the absence of operator (3) of the first capacity (4), the second capacity (5) and the third capacity (29). ) are of the same order of magnitude.

13 Apparatus according to any one of claims 4 to 12, characterized in that the processing chain (27) comprises means for applying to the first (4), second (5) capacities and when it exists, the third capacity (29) to test a same electrical signal, as well as a measurement chain (22) for detecting changes in an electrical signal induced by the presence and / or effort of the operator (3) on the sensitive module (2).

Device according to any one of claims 4 to 13, characterized in that the second capacitor (5) is formed by a plurality of pairs of electrodes (16, 17) in parallel.

15. A method of implementation of a device according to one of the preceding claims, characterized in that it cyclically measures the proximity of the operator (3) relative to the sensitive module (2) and the effort of the operator (3) on the sensitive module (2).

RECTIFIED SHEET (RULE 91) iSA / EP 12