DEVICE FOR DETECTING A KEYSTROKE OF A KEY MODULE, KEYBOARD AND METHOD FOR DETECTING A KEYSTROKE OF A KEY MODULE

Abstract

The invention relates to a device for detecting a key press of a keyboard, comprising a key module, a circuit substrate, a planar coil arranged on or in the circuit substrate, and at least one damping element, wherein the at least one damping element for damping the planar coil is movably arranged in the key module between a rest position and an actuation position, wherein the damping element executes a first actuating movement during the movement in the direction of the actuation position and executes a second actuating movement) during the movement towards the rest position, and wherein the device (10) outputs at least one electrical signal when carrying out the first actuating movement and/or the second actuating movement.

The invention also relates to a keyboard comprising one or more such devices and to a method for detecting a key press of a key module with such a device.

Claims

1. Device (10) for detecting a key press of a keyboard, comprising a key module (11), a circuit substrate (15), a planar coil (13) arranged on or in the circuit substrate (15), and at least one damping element (14), wherein the at least one damping element (14) for damping the planar coil (13) is movably arranged in the key module (11) between a rest position (27) and an actuation position (29), wherein the damping element (14) executes a first actuating movement (28a) during the movement in the direction of the actuation position (29) and executes a second actuating movement (28b) during the movement towards the rest position (27), and wherein the device (10) outputs at least one electrical signal when carrying out the first actuating movement (28a) and/or the second actuating movement (28b).

2. Device (10) according to claim 1, characterized in that the device comprises at least one control and/or monitoring device for detecting and/or processing at least one physical parameter of the planar coil (13), which parameter changes during the damping by the damping element (14), and the control and/or monitoring device is set up in such a way that when at least one change limit value of the physical parameter is reached or exceeded, the at least one electrical signal is output and/or that the signal strength of the at least one electrical signal changes as a function of the change in the physical parameter.

3. Device (10) according to claim 2, characterized in that the change limit value or the change limit values are adjustable.

4. Device (10) according to claim 2, characterized in that the control and/or monitoring device is set up in such a way that the signal strength of the at least one electrical signal is dependent on the position of the damping element (14) in the key module (11).

5. Device (10) according to claim 1, characterized in that the planar coil (13) comprises at least one winding (20) and/or is arranged on an upper side and/or an underside of the circuit substrate (15), and/or between at least two layers within a multilayer circuit substrate.

6. Device (10) according to claim 1, characterized in that the damping element (14) consists of a ferromagnetic or paramagnetic material or at least in some regions comprises a ferromagnetic or paramagnetic material.

7. Device (10) according to claim 1, characterized in that the damping element (14) forms a horizontal surface (25) which, in the actuation position (29), is aligned parallel to the circuit substrate (15) and/or to the planar coil (13).

8. Device (10) according to claim 7, characterized in that the damping element (14) forms at least one further surface (30) which extends perpendicularly or at an acute or obtuse angle to the horizontal surface (25).

9. Device (10) according to claim 1, characterized in that the damping element (14) can be moved perpendicular to the circuit substrate (15) and/or to the planar coil (13) during the first and second actuating movements (28a, 28b).

10. Device (10) according to claim 7 and according to claim 9, characterized in that a distance between the horizontal surface (25) of the damping element (14) and the circuit substrate (15) and/or the planar coil (13) changes during the vertical movement of the damping element (14).

11. Device (10) according to claim 1, characterized in that the damping element (14) is a plunger (19) of the key module (11) or the damping element (14) is arranged and/or formed on a plunger (19) of the key module (11), the plunger (19) being movably arranged in the key module (11) and the movement of the plunger (19) being the first or second actuating movement (28a, 28b) of the damping element (14) or corresponding to the first or second actuating movement (28a, 28b) of the damping element (14).

12. Device (10) according to claim 1, characterized in that the key module (11) comprises a plunger and a compression spring (18), the damping element (14) being the compression spring (18) or being arranged and/or formed on the compression spring (18), the plunger (19) being movably arranged in the key module (11) and the compression spring (19) being compressible and expandable in the key module (11), a movement of the plunger (19) being associated with a compression or expansion of the compression spring (18), the compression or expansion of the compression spring (18) being the first or second actuating movement (28a, 28b) of the damping element (14) or corresponding to the first or second actuating movement (28a, 28b) of the damping element (14).

13. Keyboard comprising one or more devices (10) according to claim 1.

14. Keyboard according to claim 13, characterized in that the keyboard has an underside and an upper side opposite the underside, the underside and/or the upper side being formed from metal or having a metallic layer or a metallic additional layer or a metallic insert.

15. Method for detecting a key press of a key module (11) of a keyboard with a device (10) according to claim 1, comprising the steps of: carrying out the first actuating movement (28a) or the second actuating movement (28b) of the damping element (14), wherein the distance between the damping element (14) and the planar coil (13) changes and the planar coil (13) is damped by the damping element (14) as a result; outputting at least one electrical signal when carrying out the first actuating movement (28a) and/or the second actuating movement (28b).

16. Method according to claim 15, characterized in that a) a physical parameter of the planar coil (13) that changes during damping by the damping element (14) is detected and/or processed, and b1) the at least one electrical signal is output when a change limit value of the physical parameter is reached or exceeded, and/or b2) the signal strength of the at least one electrical signal is changed as a function of the change in the physical parameter.

17. Method according to claim 15, characterized in that the signal strength of the at least one electrical signal changes as a function of the position of the damping element (14) in the key module (11).

Description

[0054] The invention is explained in more detail below also with regard to further features and advantages on the basis of the description of embodiments and with reference to the accompanying schematic drawings, in which:

[0055] FIG. 1 is a perspective exploded view of an embodiment of the device according to the invention,

[0056] FIG. 2 is a partial sectional view of the device from FIG. 1, wherein the damping element is in its rest position,

[0057] FIG. 3 is a partial sectional view analogous to FIG. 2, wherein the damping element is now in its actuation position, and

[0058] FIG. 4 is a schematic representation of the method according to the invention for detecting a key press of a key module.

[0059] Corresponding parts and components are each provided with the same reference signs in all figures.

[0060] FIG. 1 shows a perspective exploded view of an embodiment of the device 10 according to the invention. The device 10 comprising a key module 11, a circuit substrate in the form of a printed circuit board 15, a planar coil 13, and a damping element 14. The planar coil 13 is arranged on the upper side of the printed circuit board 15. In the printed circuit board 15, a bore 16 is provided for centering and fastening the key module 11 to the upper side of the printed circuit board 15. The key module 11 comprises a plunger 19 and a two-part housing 17. Alternatively, however, a one-piece housing or no housing is also possible.

[0061] A compression spring 18 is arranged inside the housing 17. The compression spring 18 serves to move the plunger 19 into a starting position or to hold it there until a key press is carried out. For this purpose, the plunger 19 is movably arranged in the key module 11. The compression spring 18 is compressed by pressing a key cap (not shown), placed on a free end of the plunger 19.

[0062] The damping element 14 shown in FIG. 1 consists of a ferromagnetic metallic material. Furthermore, the damping element 14 is designed as a bent part. It has a horizontal surface 25 and four further surfaces 30 running perpendicular thereto. Furthermore, the damping element 14 has two opposing recesses 22 on two of the further surfaces 30, which are opposite one another, for mechanical, in particular form-fitting, attachment to the plunger 19 of the key module 11. Two opposite lugs 23 are formed on the plunger 19 for engaging in the recesses 22 of the damping element 14.

[0063] During a first actuating movement of the damping element 14 from a rest position shown in FIG. 2 in the direction of an actuation position shown in FIG. 3, triggered by a pressure on the plunger 19, the damping element 14 approaches the printed circuit board 15 and thus the planar coil 13 perpendicularly, the distance between the actuation element 14 and the planar coil 13 decreases, the planar coil 13 is damped by the movement of the damping element 14. In the event of a reversed second actuating movement of the damping element 14 from the actuation position into the rest position, the damping element 14 moves away from the printed circuit board 15 and thus from the planar coil 13. The distance between the damping element 14 and the planar coil 13 increases, the planar coil 13 is damped by the movement of the damping element 14.

[0064] A physical parameter of the planar coil 13 that changes due to the damping is detected and/or processed by a control and/or monitoring device (not shown in the figures). For example, an electrical voltage can be measured. When a change limit value (threshold value) is reached or exceeded, at least one electrical signal is triggered by the control and/or monitoring device, which signals the actuation or the end of the actuation of the corresponding key. Alternatively or additionally, a strength of the at least one output signal can also be changed.

[0065] The planar coil 13, which is arranged on the upper side of the printed circuit board 15, has a plurality of complete windings 20, specifically seven, which are arranged one inside the other in a spiral shape on a plane. Each winding is substantially square in shape with rounded corners. Overall, the planar coil 13 thus also has a square shape with rounded corners. The shape of the windings 20 and of the planar coil 13 as a whole is adapted to the shape and dimensions of the key module 11.

[0066] Furthermore, an LED 21 for illuminating the key module 11 is arranged on the upper side of the printed circuit board 15. It can be a single-color or multi-color LED 21, so that color gradients can be implemented. The LED 21 is arranged on the upper side of the printed circuit board 15 in such a way that it is still within the housing 17 of the key module 11.

[0067] FIG. 2 shows the device 10 according to the invention in the rest position 27 of the damping element 14 and the starting position of the key module 11 or the starting position of the plunger 19. The compression spring 18 presses the plunger 19, with which the damping element 14 is positively connected, against an upper stop 24 of the housing 17 of the key module 11. Without an external force acting on the plunger 19, the plunger remains at the upper stop 24 due to the compression spring 18. Only when the plunger 19 is pressed, the plunger 19 is brought into its pressed position and the damping element 14 is brought into the actuation position shown in FIG. 3. In the rest position, the damping element 14 arranged on the plunger 19 is at a greater distance from the printed circuit board 15 than in the actuation position.

[0068] The horizontal surface 25 of the damping element 14 is at a maximum distance from the printed circuit board 15 and at the same time from the planar coil 13. The damping element 14 damps the planar coil 13 only slightly or not at all because of the distance from the printed circuit board 15.

[0069] In FIG. 3, the key module 11 and the plunger 19 are shown in a pressed position and the damping element 14 is shown correspondingly in an actuation position. The distance between the horizontal surface 25 of the damping element 14 and the printed circuit board 15 and at the same time from the planar coil 13 is minimal. The movement of the plunger 19 with the damping element 14 is limited by a lower stop 26 (bottom) of the housing 17 of the key module 11. The compression spring 18 is maximally compressed in the pressed position of the key module 11. The planar coil 13 is significantly more strongly damped in the actuation position of the damping element than in the rest position and a change in a physical parameter, for example an electrical voltage, is measured accordingly. This change takes place continuously during the actuating movement of the damping element 14. When a change limit value (threshold value) is reached or exceeded during the actuating movement of the damping element 14, at least one electrical signal is triggered. As an alternative or in addition, the strength of the electrical signal output can also be changed, preferably in accordance with the changing position of the damping element 14 relative to the planar coil 13. When the pressing of the key ends, the plunger 19 is moved back into the starting position by the force of the compressed compression spring 18 and analogous processes take place. The plunger 19 of the key module 11 can then be actuated again.

[0070] FIG. 4 illustrates the method according to the invention for detecting a key press of a key module 11. The rest position of the damping element is denoted by reference sign 27. The key module 11 is in its starting position; there is no compressive force acting on the plunger 19 from above. The compression spring 18 adopts the form that is as relaxed as possible and holds the plunger 19 with the damping element 14 against the upper stop 24. The damping element 14, in particular the horizontal surface 25 of the damping element 14, is at the greatest possible distance from the printed circuit board 15 and/or the planar coil 13. The planar coil 13 is not or is hardly damped in this state.

[0071] The actuation position of the damping element 14 is denoted by reference sign 29 in FIG. 4. The key module 11 is in its depressed position. When the key and thus the plunger 19 are pressed by an operator, the key module is moved from its starting position into its pressed position. The damping element 14 is thereby moved from its rest position 27 into its actuation position 29 by the first actuating movement 28a shown symbolically in FIG. 4. If the pressure on the key and thus the plunger 19 decreases or disappears completely, the plunger 19 is moved from its depressed position to its starting position due to the restoring force emanating from the compression spring 18 and the damping element 14 is thereby moved from its actuation position 29 into its rest position 27 by the second actuating movement 28b, shown symbolically in FIG. 4. The restoring force of the compression spring 18 is at least sufficiently great that the plunger 19 only reaches the starting position as a result of this restoring force. At the same time, the compression spring 18 has the effect that the key module 11 can only be actuated with the application of a specific force.

[0072] During the first actuating movement 28a, the plunger 19 with the damping element 14 is moved from its rest position 27 in the direction of the actuation position 29. The damping element 14 continuously approaches the printed circuit board 15 and the planar coil 13. “Approaching” is to be understood as a reduction in the distance between the damping element 14 and the planar coil 13. The closer the damping element 14 and in particular the horizontal surface 25 of the damping element 14 comes to the planar coil 13, the greater the influence of the damping element 14 on the physical parameters of the planar coil 13. As a specific example, it can be stated that an electrical voltage which is applied to the planar coil 13 changes as the damping element 14 approaches.

[0073] The actuation position 29 is that position of the damping element 14 in which the change limit value (threshold value) of the measured physical parameter is reached or has already been exceeded and thus at least one electrical signal is triggered or has already been triggered. The specific switching point is not defined by a mechanical stop in the key module 11. Rather, the switching point is dependent on the defined or set change limit value (threshold value). Thus, the damping element 14 and thus also the plunger 19 of the key module 11 can also be moved beyond the switching point until the actuation position is reached with a corresponding change limit value. The movement of the plunger 19 and thus of the damping element 14 is finally limited only by the lower stop 26 of the key module 11. The same applies analogously to the second actuating movement 28b, by means of which the damping element 14 is moved back into its rest position 27 and the plunger 19 is moved back into its starting position.

LIST OF REFERENCE SIGNS

[0074] 10 Device

[0075] 11 Key module

[0076] 13 Planar coil

[0077] 14 Damping element

[0078] 15 Circuit substrate, designed as a printed circuit board

[0079] 16 Bore

[0080] 17 Housing

[0081] 18 Compression spring

[0082] 19 Plunger

[0083] 20 Winding

[0084] 21 LED

[0085] 22 Recess

[0086] 23 Lug

[0087] 24 Upper stop

[0088] 25 Horizontal plane

[0089] 26 Lower stop

[0090] 27 Rest position

[0091] 28a First actuating movement

[0092] 28b Second actuating movement

[0093] 29 Actuation position

[0094] 30 Further surface