阅读说明：本技术 具有包括柔性膜的至少一个透明键的***设备 (Peripheral device having at least one transparent key comprising a flexible membrane ) 是由 L·费弗尔 Y·普乔尼 于 2019-01-16 设计创作，主要内容包括：本发明涉及一种外围设备(1),具有至少一个透明键(2),该透明键能够在压力的作用下致动,并装在形成于壳体(10)的第一面(10a)上的开口(11)中,外围设备(1)具有用于监控和检测施加在键(2)上的压力的系统(13)和用于通过每个键(2)而经由分别的显示路径(5)显示符号(3)的至少一个屏幕(4),监控和检测系统(13)具有柔性膜(14),该柔性膜提供致动力和压力反馈作用,并且具有至少一个孔口(17),每个孔口限定用于键(2)的显示路径(5),并且每个孔口(17)由与键(2)配合的边界(17a)限定。(The invention relates to a peripheral device (1) having at least one transparent key (2) which can be actuated under pressure and is fitted in an opening (11) formed on a first face (10a) of a casing (10), the peripheral device (1) having a system (13) for monitoring and detecting the pressure exerted on the key (2) and at least one screen (4) for displaying a symbol (3) by each key (2) via a respective display path (5), the monitoring and detecting system (13) having a flexible membrane (14) which provides an actuation force and a pressure feedback action and has at least one aperture (17), each aperture defining a display path (5) for the key (2), and each aperture (17) being defined by a border (17a) cooperating with the key (2).)

1. A peripheral device (1) comprising at least one transparent key (2), said transparent key (2) being actuatable under pressure and engaging in an opening (11) arranged on a first face (10a) of a casing (10), said key (2) cooperating with the first face (10a) of the casing (10), said peripheral device (1) comprising: a control and detection system (13) of the pressure exerted on said keys (2); and at least one screen (4) allowing the display of symbols (3) by each of said keys (2) respectively via a display path (5), characterized in that said control and detection system (13) comprises a flexible membrane (14) ensuring the actuation force and the pressure feedback action and comprising at least one aperture (17), each of said apertures defining one display path (5) for one key (2), and each of said apertures (17) being defined by a border (17a) cooperating with a key (2).

2. A peripheral device (1) according to claim 1, characterized in that it comprises a series of keys (2).

3. The peripheral device (1) according to claim 1 or 2, wherein each key (2) comprises a lower peripheral region (7b) supported on the border (17a) of the aperture (17) of the flexible membrane (14).

4. The peripheral device (1) according to any one of claims 1 to 3, wherein the flexible membrane (14) comprises a skirt (18) extending from a base plate (19) and defining, at its free end, a border (17a) of each aperture (17) of the flexible membrane (14).

5. The peripheral device (1) according to any one of claims 1 to 4, wherein the border (17a) of each aperture (17) of the flexible membrane (14) cooperates with the bottom of a groove (8) arranged around the periphery of each key (2).

6. The peripheral device (1) according to any one of claims 1 to 5, wherein the control and detection system (13) comprises: -detection means (15) for detecting the pressure exerted on said key (2) separated from said flexible membrane (14).

7. Peripheral device (1) according to claim 6, characterized in that said detection means (15) have a support surface for said flexible membrane (14).

8. A peripheral device (1) according to claim 6 or 7, characterized in that said detection means (15) comprise one channel (16) for each of said display paths (5).

9. Peripheral device (1) according to any one of claims 6 to 8, characterized in that said detection means (15) comprise a switch structure on which at least one tab (9) fixed to said key (2) acts to provide an actuation signal when pressure is applied to said key (2).

10. The peripheral device (1) according to claim 9, wherein the flexible membrane (14) comprises a passage hole (20) for each tab (9) fixed to the key (2).

11. Peripheral device (1) according to any of claims 1 to 5, characterized in that said control and detection system (13) is a flexible membrane comprising a switch structure.

12. Peripheral device (1) according to any of claims 1 to 11, characterized in that it comprises, for each key (2), at least one guiding structure (21) of the key (2).

13. The peripheral device (1) according to claim 12, characterized in that said guide structure (21) is constituted by one tab (9) fixed to said key (2) and by two guides (22) projecting from the inner surface of the first face (10a) of said casing (10) to define between them a slideway for said tab (9) at a height allowing to guide said tab (9) in said slideway during the whole displacement stroke caused by the pressure exerted on said key (2).

14. A peripheral device (1) according to claim 12 or 13, characterized in that it comprises, for each key (2), four guide structures (21).

15. The peripheral device (1) according to claim 14, characterized in that the guiding structures (21) of the keys are aligned in pairs along two intersecting axes.

16. Peripheral device (1) according to any of claims 1 to 15, characterized in that the screen (4) is a bi-stable screen, preferably an electrophoretic screen.

17. A peripheral device (1) according to any of claims 1 to 16, characterized in that the peripheral device is an electronically controlled keyboard.

18. An article comprising a peripheral device (1) according to any one of claims 1 to 17.

Technical Field

The present invention relates to a peripheral device comprising at least one transparent key (button) that can be actuated under pressure and is provided with a system that allows actuation forces and pressure feedback effects after the application of pressure on the key.

Background

Generally, a peripheral device having a transparent key includes: a housing provided on a front surface thereof, the housing having an opening for the key to be engaged therein; and at least one screen on which a symbol or an image to be viewed through the transparent key is displayed. These peripheral devices also comprise systems allowing to detect the pressure exerted on the keys. These peripheral devices also include a tactile system that allows the user to feel when a key is effectively depressed (actuation force), and a system for pressure feedback action after pressure is applied on the key.

Different control systems, namely haptic systems and systems for pressure feedback effects are known. For example, application WO2016/142881 describes a device for a computer such as a computer keyboard, comprising a casing provided on its front face, which casing has (a) opening(s) in which at least partially transparent keys are engaged, through which openings symbols displayed on a screen can be viewed. The apparatus further comprises: a system for detecting the pressure exerted on the key and a system for ensuring the actuation force, the system being in the shape of a dome (dome) that is crushed when pressure is exerted on the key; and a pressure feedback action system in the shape of scissors, hinges or springs.

A first drawback associated with systems with mechanical pressure feedback is that the system deteriorates over time. In fact, these pressure feedback action systems fail (wear out) over time.

A second disadvantage associated with mechanical pressure feedback action systems is the haptic effect, which is not good enough and degrades over time.

In addition, in document WO2016/142881, the key mechanism cooperates with the latter over a large surface and is visible through a transparent key. Therefore, there is a risk of causing poor screen display by the transparent key.

Another problem relates to the displacement travel of the keys caused by the pressure exerted on the keys, which must be stable and balanced. According to a particular embodiment, document WO2016/142881 describes lugs (lugs) located on the periphery of the key, able to cooperate with complementary housings located on the inner surface of the housing, so as to allow the key to be positioned when no pressure is applied to the key. Furthermore, the stability of the key during its displacement stroke is not guaranteed.

Another example of a tactile and pressure feedback system is described in application US 2013/0082932. The present application describes a dynamic display keyboard comprising a plurality of at least partially transparent keys, a mat (mat), an optical element for each key and at least one screen. The pad is flexible and may comprise a plurality of protruding elements, such as domes with trapezoidal profile, which are able to ensure the actuation force and pressure feedback action of the key located above by generating (undersgo) deformations. The pad also includes attachment element(s) that are attachable to the plurality of keys and allow detection of pressure exerted on the keys when in contact with the capacitive screen. The pad includes aperture(s) to allow light to pass from the screen below to the transparent portion of the key above.

A disadvantage associated with this system is that the key is not adequately maintained during the displacement stroke that occurs with the application of pressure. In practice, such floating mounting can lead to uncertainty in the position of the key.

Another example is shown in application US 2012/0160653, which describes a keyboard containing keys made of a transparent or light-transmitting material. The keyboard further includes a layer located below the keys, and a pattern including opaque portions and light-transmitting portions is printed on the layer. Thus, the pattern of the layer is visible through the keys located underneath it due to the presence of the light source. The key is also disposed over the resilient member above the switch. When pressure is applied on the key, the elastic member deforms, thereby allowing the switch to be actuated.

A disadvantage associated with this system is that the keys are held in place and guided as pressure is applied to the keys. In fact, it is necessary to keep the keys in place and guide them during their displacement stroke, in order to avoid any uncertainty of positioning and good translation of the keys with respect to the casing when applying the pressure.

Disclosure of Invention

The object of the present invention is to overcome the drawbacks of the prior art. To this end, a first object of the invention is to provide a peripheral device comprising a system with a pressure feedback effect that ensures good tactile characteristics and does not fail over time, and in particular is smaller than mechanical pressure feedback effect systems. Preferably, the pressure feedback system allows a good view of the screen through the transparent keys.

It is an object of the invention to provide a peripheral device comprising a key which is accurately positioned while being guided during its displacement.

Another object of the invention is to propose a peripheral device comprising a key whose guidance is ensured over the entire displacement travel of the key caused by the pressure exerted on the key. More specifically, the displacement stroke of the key is stable and balanced.

To this end, the peripheral device according to the invention is such that it comprises at least one transparent key which can be actuated under pressure and which engages in an opening arranged on the first face of the casing, the peripheral device comprising: a system for controlling and detecting pressure exerted on the keys; and at least one screen allowing the display of symbols by each key via a display path, respectively, the control and detection system comprising a flexible membrane ensuring the actuation force and pressure feedback action and comprising at least one aperture, each aperture defining (delimit) one display path for a key and each aperture being defined by a boundary cooperating with a key.

In the context of the present invention, an "actuation force" refers to the force required to exert a pressure on a key to be detected.

In case one or the other of the following features are not mutually exclusive, the peripheral device according to the invention preferably has one or the other of the following features, taken alone or in combination:

-the peripheral device comprises a series of keys;

-the lower peripheral region of each key bears (bear) on the border of the aperture of the flexible membrane;

the flexible membrane comprises a skirt extending from the base plate and delimiting each aperture of the flexible membrane at its free end;

the border of each aperture of the flexible membrane cooperates with the bottom of a groove arranged around the periphery of each key;

the control and detection system comprises means for detecting the pressure exerted on the individual keys of the flexible membrane;

the detection device has a support surface for the flexible membrane;

the detection means comprise one channel for each display path;

-the detection means comprise a switch structure on which at least one tab (tab) fixed to the key acts to provide an actuation signal when pressure is applied to said key;

the flexible membrane comprises a hole for the passage of each tab fixed to the key;

-the control and detection system is a flexible membrane comprising (incorporate) switch structures;

-the peripheral device comprises at least one key guiding structure for each key;

the key cooperates with the first face of the housing, preferably with two guides (extended projections) projecting from the inner surface of the first face of the housing;

the guide structure is constituted by a tab fixed to the key and by two guides projecting from the inner surface of the first face of the casing to define between them a slideway for said tab, at a height allowing to guide said tab in the slideway during the whole displacement stroke caused by the pressure exerted on said key;

the peripheral device comprises four guiding structures for each key;

-the key guide structures are aligned in pairs along two intersecting axes;

the screen is a bi-stable screen, preferably an electrophoretic screen; and

-the peripheral device is an electronically controlled keyboard.

Another subject of the invention relates to an article (article) comprising a peripheral device according to the invention. For example, such an item may be a computer, a machine tool, a medical instrument, a hi-fi (hi-fi) device, an instrument panel, a personal digital assistant, a control panel, or a remote control.

Drawings

The description given below with reference to the accompanying drawings will give rise to various other features, which illustrate by way of non-limiting example embodiments of the subject matter of the present invention.

Fig. 1 is a perspective view of a peripheral device according to the present invention.

Fig. 2 is an exploded perspective view of a stack of various elements constituting a peripheral device according to the present invention.

Fig. 3 is a cross-sectional view of a portion of a peripheral device according to the present invention.

Fig. 4 is a perspective view of a flexible film according to the present invention, on which transparent keys are placed.

FIG. 5 is a perspective view of the inner surface of the housing including openings, wherein a key is mounted in one of the openings of the housing.

Fig. 6A to 6C are perspective views showing the installation of the transparent key with respect to the guide member thereof.

Detailed Description

The peripheral device according to the invention may be an electronically controlled keyboard, such as a computer peripheral, a hi-fi peripheral, a peripheral of a machine tool, a peripheral of a dashboard, a personal digital assistant or a control panel. According to a particular embodiment, the peripheral device according to the invention is a computer peripheral device, such as a computer keyboard or a mouse.

As can be seen from the figure, the object of the invention relates to a peripheral device 1 comprising at least one transparent key 2 through which a symbol 3 displayed on a screen 4 can be observed via a display path 5. For the case where the peripheral device comprises a plurality of transparent keys 2, the peripheral device 1 comprises one display path for each key 2. Advantageously, the peripheral device 1 does not comprise opaque keys.

The "display path" refers to a path that allows a symbol or an image displayed on the screen 4 to be viewed through various constituent elements of the peripheral device including the transparent key 2.

In the context of the present invention, a key may be a block having a cross section (section) of any shape, for example a circular or trapezoidal cross section, in particular a block having a parallelogram, rectangle or square cross section. Each key 2 comprises an upper surface 6a, on which pressure can be exerted, and a lower surface 6b, which extends substantially opposite to the upper surface 6a, connected together by a peripheral zone 7. According to one embodiment of the invention, each key 2 comprises a lateral peripheral zone 7a extending from the upper surface 6a and extended by a lower peripheral zone 7b, the cross section of which is substantially parallel to the upper surface 6a and to the lower surface 6b, respectively, as shown in fig. 3. According to a particular embodiment, each key 2 comprises a groove 8 arranged around the entire periphery of the peripheral region 7 and defining a lower peripheral region 7 b.

According to an advantageous characteristic of the invention, each key 2 comprises at least one tab 9, which in the example shown is made in one piece with the key. Of course, the tabs may be added by assembling the tabs 9 to the keys 2 in any suitable manner. Each tab 9 extends from the key 2 and from its peripheral region 7. In other words, each tab 9 is arranged to protrude with respect to the upper surface 6a of the key 2. When the key is in the shape of a block of trapezoidal section, the tab 9 may protrude from the peripheral region 7 at an angle or on the side of the upper surface 6a of the key 2.

According to a preferred embodiment, the screen 4 allows a dynamic display of the symbols 3. In other words, the symbol 3 displayed for each key 2 can be modified according to a command given by the user or by the application. The screen 4 may be an LCD (liquid crystal display), TFT-LCD (thin film transistor liquid crystal display), LED (light emitting diode), OLED (organic light emitting diode), AMOLED (active matrix OLED), IPS screen (in-plane switching), VA (vertical alignment), TN (twisted nematic), cathode screen, plasma screen, or electrophoretic screen. The screen 4 is preferably a bi-stable screen, in particular an electrophoretic screen.

The peripheral device 1 comprises a casing 10 constituted by a first face 10a provided with an opening 11 for each key 2 and by an opposite second face 10 b. Therefore, as shown in fig. 1 and 3, each key 2 is protruded (rise) on either side of the first face 10a of the casing 10, and when no pressure is applied to the key 2, the key 2 passes through (cross) via the opening 11. In the context of the present invention, the first face 10a of the casing 10 corresponds to an upper wall of the casing 10 provided with an opening 11 for each key 2, and the second face 10b of the casing 10 corresponds to a lower wall of the casing 10.

According to the embodiment shown in fig. 2, the peripheral device 1 further comprises an electronic circuit 12 which ensures the transmission of the functions of the peripheral device 1, in particular the actuation signals.

The peripheral device 1 also comprises a control and detection system 13 for controlling and detecting the pressure exerted on the keys 2. The control and detection system 13 not only imparts tactile properties to the key, in particular an actuation force and a pressure feedback effect after applying a pressure on the key 2, but also allows to detect the pressure applied on the key.

According to the invention, the control and detection system 13 comprises a flexible membrane 14 which ensures the actuation force and the pressure feedback action after the pressure is applied on the key 2. The flexible membrane 14 helps to hold the key 2 in place (in place) during the absence of pressure exerted on the key 2 and during the displacement stroke caused by the exerted pressure.

According to a first embodiment, shown in figures 2 and 3, the control and detection system 13 comprises a flexible membrane 14 and detection means 15 for detecting the pressure exerted on the keys 2 separated from the flexible membrane 14. As shown in fig. 3, the detection device 15 advantageously has a support surface for the flexible membrane 14.

According to another embodiment, not shown in the figures, the control and detection system 13 may be a flexible membrane as described in the context of the present invention, and also integrates (integral) a switch structure that allows to provide an actuation signal when pressure is exerted on the keys 2. Such a flexible membrane with integrated switch structure allows to impart desired tactile properties due to the flexible nature and the geometry of the membrane and to detect the pressure exerted on the key due to the integrated switch structure.

According to the embodiment shown in fig. 2 and 3, the peripheral device according to the invention comprises an electronic circuit 12, a screen 4, a detection means 15, a flexible membrane 14, at least one key 2 and a housing 10. More specifically, the peripheral device 1 may comprise a casing 10 constituted by a first face 10a provided with openings 11 through which the keys 2 pass, and by a second face 10b able to bear on a flange edge 10c of the first face. The other elements constituting the peripheral device 1 are positioned inside the casing 10, which is then locked in the closed position by any suitable means.

As shown in fig. 1 to 3, the keys 2 are engaged through the openings 11 of the first face 10a of the housing 10 to protrude from the first face 10a of the housing 10. According to this embodiment, the flexible membrane 14 is located below the key 2. The flexible membrane 14 is located above a detection device 15, which in turn has a support surface for the flexible membrane 14. The detection means 15 are in turn positioned above the screen 4 on which the symbol 3 is displayed for each key 2. Finally, the electronic circuit 12 may be located below the screen 4 and above the second face 10b of the casing 10. In other words, the key 2 can be positioned between the first face 10a of the casing 10 (through the opening 11) and the flexible membrane 14, the detection means 15 being located between the flexible membrane 14 and the screen 4, which in turn is in contact with the electronic circuit 12. This arrangement is not critical and another stacking can be made within the framework of the invention. For example, the screen 4 may be located between the flexible membrane 14 and the detection device 15.

As shown in fig. 2 and 3, when the detection means 15 are positioned between the screen 4 and the transparent key 2, they comprise one channel 16 for each display path 5. The channel 16 is of similar dimensions and has a surface at least as large as the opening 11 accommodating the adjacent key 2. The channel 16 of the detection device 15 and the opening 11 of the first face 10a of the housing 10 are located in an overlapping or coinciding position. Thus, the detection means 15 are not visible through the transparent key 2 and the border 16a of the channel 16 defines the display path 5.

The detection means 15 may comprise a touch structure or, preferably, a switch structure on which at least one tab 9 fixed to the key 2 acts (act) so as to provide an actuation signal when pressure is exerted on the key 2 and, for example, so as to generate an electrical signal. For example, the switch structure may be constituted by two insulating sheets covered on their inner surfaces with a conductive surface and separated by an insulating sheet comprising openings. Pressure is applied to the switch structure at the location of the opening of the insulating sheet, bringing the two conductive surfaces into contact. Such switch structures, which may be suitable in the context of the present invention, are known to the person skilled in the art and will not be described in detail here.

Each tab 9 is positioned perpendicular to the opening in the insulating sheet and has a height suitable for acting on the detection means 15. In the example shown, each tab 9 has a connecting branch 9a which extends substantially parallel to the upper surface 6a of the key 2 and is elongated at right angles by a vertically extending actuating branch 9 b. When pressure is exerted on the key 2, the tab 9, through its actuation branch 9b, can come into contact with the detection means 15, which then provide an actuation signal.

According to the embodiment shown, the free end of the actuation branch 9b comprises a stud, in particular a stud with a circular cross section. Such studs allow to concentrate stresses on a small surface and are particularly advantageous for detecting the pressure exerted on the key 2.

Although not shown, the free ends of the actuating branches may be devoid of any studs.

The flexible membrane 14 comprises at least one aperture 17 associated with each key 2, the aperture 17 having substantially similar dimensions to the opening 11 into which the key 2 is inserted and having a surface substantially smaller than the opening 11. Preferably, the orifice 17 and the opening 11 coincide, the orifice 17 being below the opening 11. The aperture 17 and the opening 11 are concentric, the key 2 being positioned between the aperture 17 and the opening 11. Each aperture 17 comprises a boundary 17a which defines the display path 5 for each key 2. Thus, in the embodiment shown in fig. 2 and 3, the display path 5 for the transparent key 2 is defined by the upper surface 6a of the key 2, the opening 11 of the first face 10a of the casing 10, the border 17a of the aperture 17 of the flexible membrane 14 cooperating with the key 2, and the border 16a of the channel 16 of the underlying detection device 15. In other words, the upper surface 6a of each key 2 coincides with the aperture 17 of the flexible membrane 14 and with the channel 16 of the detection device 15.

Each aperture 17 of the flexible membrane 14 is defined by a border 17a cooperating with the key 2. More specifically, as shown in fig. 3, this border 17a may cooperate with the peripheral zone 7 of the key 2, in particular with the lower peripheral zone 7 b. According to a particular embodiment, the border 17a of the aperture 17 of the flexible membrane 14 cooperates with the bottom of the groove 8 arranged on the periphery of the key 2, which helps to hold the key in place and guide it during its displacement. According to a preferred embodiment, each key 2 bears by its lower peripheral zone 7b on the border 17a of the aperture 17 of the flexible membrane 14. Thus, in the context of the present invention, the contact surface between the flexible membrane 14 and the key 2 is weak (weak), since said contact takes place over the entire periphery of the key 2 and contributes to holding the key in place and guiding it over its entire displacement travel.

According to the embodiment shown in fig. 2 to 4, the flexible membrane 14 comprises, for each orifice 17, a skirt 18 projecting from a base plate 19. Each skirt 18 then defines, at its free end, the boundary 17a of the aperture 17 of the flexible membrane 14, thus defining the display path 5. In other words, the flexible membrane 14 may be of planar shape and provided with an aperture 17 for each key 2 in contact therewith, the border 17a of the aperture 17 formed by the end of the skirt 18 being able to cooperate with the key 2 and in particular with the groove 8 thereof.

The skirt 18 is preferably of a truncated cone shape, projecting in the direction of the superimposed keys, in the exemplary embodiment shown in the figures, a large base being located at the base plate 19, and a small base forming the boundary 17a of the orifice 17. According to this embodiment, this skirt 18 allows ensuring the desired actuation force and pressure feedback effect, and also allows a good positioning of the key 2 with respect to the opening 11 of the housing 10. The geometry of the skirt 18 is not limited per se and can be adjusted by the person skilled in the art according to the desired technical characteristics.

Alternatively, according to another embodiment, the keys 2 are joined (link) by bonding of their peripheral regions 7 to the flexible membrane 14.

The flexible membrane 14 deforms beyond a certain force (actuation force) under the effect of pressure exerted on the key 2 with which it cooperates. The actuation force and pressure feedback effect can be adjusted according to the properties of the membrane, in particular its geometry and stiffness. This is a routine operation for the person skilled in the art and is not described in detail here.

The flexible film 14 may be opaque, translucent, or even transparent. According to a particular embodiment, the film is opaque. According to another particular embodiment, the film is translucent, and preferably transparent.

Therefore, since the contact surface between the key 2 and the flexible film 14 is small, the presence of the flexible film 14 is hardly seen or not seen through the transparent key 2. In addition, if the flexible film 14 is translucent or transparent, the flexible film 14 is also barely visible or invisible due to its translucent or transparent nature.

The flexible membrane 14 may be made of any polymeric material, such as silicone, rubber such as EPDM (ethylene-propylene-diene monomer) rubber, or polyurethane elastomer; or latex (latex). According to a preferred embodiment, the flexible membrane 14 is made of silicone.

The stiffness of the flexible membrane 14 and its geometry allow for adjustment of the actuation force and the pressure feedback force.

According to the embodiment shown in fig. 4, the flexible membrane 14 also comprises a passage hole 20 for each tab 9 of the key 2, in particular for the actuation branch 9 b. This passage hole 20 thus allows the tab 9 fixed to the key 2 to pass through the flexible membrane 14 and thus come into direct contact with the detection means 15 which provide the actuation signal when pressure is applied to said key. The presence of the passage hole 20 allows to detect the pressure exerted on the key 2.

According to one embodiment of the invention, the peripheral device 1 further comprises at least one structure 21 for guiding the key 2. Such a guide structure 21 allows a stable and balanced displacement stroke during the application of pressure on the key 2.

In the context of the present invention, the key 2 is guided in translation with respect to the housing 10 by the cooperation of the key with the first face 10a of the housing 10. Thus, the guide structure allows vertical displacement of the key relative to the housing when pressure is applied on the key. In the example shown in the figures, the guide structure 21 is constituted by a tab 9 fixed to the key 2 and by two guide portions 22 projecting from the inner surface of the first face 10a of the casing 10. According to this embodiment, the tabs 9 allow to detect the pressure exerted on the key 2 and to guide said key during the movement of the key 2.

As shown in fig. 5 and 6A to 6C, the two guides 22 define between them a slideway for the complementary tab 9. Thus, the tab 9, in particular the actuation branch 9b, slides in the slide defined by the two guides 22.

The height of the guide 22 must be large enough to guide the tab 9 throughout the displacement stroke after the pressure is exerted thereon. In fact, the lower height does not allow a good guidance of the key 2 during its entire travel. Preferably, the maximum dimension D of the cross section of the guide portion 22 and the length L of the guide portion 22 are L > 2.5D. In the case where the guide portion 22 is circular in cross section, the maximum dimension D corresponds to the cross-sectional diameter.

In the installed position of the peripheral device, the guide 22 helps to hold the membrane 14 in place.

The guide 22 may have different shapes, but is advantageously a separate element in the form of a lug, pad or cylinder. The two guides 22 defining the same slide advantageously have substantially the same shape and dimensions. The guide 22 projecting from the inner surface of the first face 10a of the housing 10 is an insert or preferably forms an integral part of the housing 10.

Preferably, the width of the slide defined by the two guides 22 has a dimension substantially equal to the width of the actuation branch 9b, apart from the operating gap, which makes it possible to avoid the support (bridging) of the actuation branch 9 b. Preferably, the slide defined by the guide 22 is adjusted to the actuation branch 9b so as to avoid the support of the actuation branch 9b and to make it slide in the slide.

Advantageously, the guide portion 22 is made of a plastic material that is self-lubricating or almost self-lubricating, or of a plastic material covered with varnish. Such plastic and varnish materials which are suitable for use in the context of the present invention are well known to the person skilled in the art and will not be described in detail here. According to this embodiment, the friction coefficient generated by the sliding of the actuation branch 9b in the slideway is minimized.

In the context of the present invention, the term "coefficient of friction" refers to the force resulting from the friction of the actuation branch 9b in movement relative to the guide 22.

The peripheral device 1 may comprise at least one guiding structure 21, preferably at least three guiding structures, in particular four guiding structures, per key 2. Of course, the guiding structure itself may be of any known type and be different from that described above.

For the case where the peripheral device 1 comprises a plurality of guide structures 21, according to the embodiments shown in fig. 5, 6A, 6B and 6C, the guide portions 22 of two adjacent guide structures 21 are not interconnected. Alternatively, according to another embodiment not shown, the guide portions 22 of two adjacent guide structures 21 are interconnected.

According to the embodiment shown in fig. 5, 6A, 6B and 6C, the two faces of the guide 22 together define a slideway for two adjacent keys. In other words, the guides 22 may have two faces at 90 °, each face defining, with the other adjacent guide 22, a slideway for a separate tab 9.

According to a first embodiment shown in fig. 5, 6A, 6B and 6C, the peripheral device comprises four guiding structures 21 for each key. According to this embodiment, four guide structures 21 are aligned in pairs along two intersecting axes. Advantageously, the guide structures 21 of the keys 2 aligned along the same axis are provided on either side of the keys 2.

In the case where the key 2 has a trapezoidal cross section (in particular, a parallelogram, rectangle or square cross section), the four guide structures 21 are preferably aligned in pairs along the diagonal of the opening 11 of the first face 10a of the housing 10. In this case, each guide structure 21 is located at a corner of the key 2. Then, the tabs 9 protrude from the corners of the keys, and the guide portions 22 are provided on either side of each diagonal line of the opening 11 of the first face 10a of the housing 10.

Alternatively, four guide structures 21 of keys 2 of trapezoidal section (in particular parallelogram section, rectangular section or square section) are provided along one side of the keys 2. In this case, the guide structures 21 are aligned in pairs along the perpendicular bisector (bisactor) of the opening 11 of the first face 10a of the housing 10. In this case, the tab 9 protrudes from the peripheral region 7 of the key 2, and the guide portions 22 are provided on either side of the vertical bisector of the side face of the key 2.

As shown in fig. 5, 6A, 6B and 6C, for the particular case of a key with a square cross-section, the four guide structures 21 are advantageously aligned in pairs along two perpendicular axes (for example perpendicular bisectors or preferably diagonals of the side faces).

In the case of a key with a circular cross-section, the four guide structures 21 are advantageously aligned in pairs along two perpendicular axes.

According to a second embodiment, the peripheral device comprises three guiding structures 21 for each key. According to this embodiment, the three guide structures 21 are uniformly distributed along a circle having the same center as the key 2 and along axes intersecting at 120 °.

According to the embodiment shown in fig. 5, 6A, 6B and 6C, the peripheral device comprises four guiding structures for each key 2 with a square cross-section: tabs 9 project from the corners of each key 2 and, when pressure is applied to the key 2, the tabs 9 slide in the slide channels defined by the lugs 22 projecting from the inner surface of the first face 10a of the housing 10 (which includes the openings 11 for the keys 2). Each lug 22 comprises two faces at 90 ° to define a slideway for two adjacent keys.

The guide structure 21 according to the invention not only allows a stable and balanced displacement travel of the key 2 when pressure is exerted on the key, but also frees the display path 5 (without interference).

The invention is not limited to the examples described and shown, since various modifications can be made without departing from the scope thereof.