Dome actuator structure and dome switch including the structure

Abstract

The present invention provides a dome actuator structure (10) for use in a dome switch (200), the dome actuator structure (10) comprising: a lower substantially horizontal lower dome (12); an upper actuator portion (14) attached to the lower dome (12) and positioned vertically above the lower dome (12) so that depression of the actuator portion (14) results in depression of the lower dome (12); and a side arm (36) coupling the actuator portion (14) to the lower dome (12), wherein the side arm (36) and the lower dome (12) are formed from a common piece of material, and wherein the actuator portion is an actuation block (14) fixed to the side arm (36) and made of a plastic material or a synthetic material or made of a natural or synthetic elastomer.

Description

Technical Field

[0001] The present disclosure relates to a dome switch suitable for use in an electrical or electronic device. Background Art

[0002] Dome switches are well known and are often used in consumer electronics to implement buttons. For example, various electronic devices often include buttons that a user can press to invoke various operations on such devices. Such buttons can be used, for example, as function buttons.

[0003] A dome switch consists of a conductive switch or trip element having the general shape of a dome made of metal or plastic which can be temporarily deformed by a user's pressure to cause a switching action, i.e. establish a switch mode which was previously "off".

[0004] When the user's pressure on the button is removed, the dome returns to its original shape and the switch mode returns to its "off" state.

[0005] Advantageously, the dome switch may provide tactile feedback to the user.

[0006] The conventional assembly of a push button implemented by a dome switch is as follows.

[0007] For example, the dome must be placed on a substrate, and the corresponding structure typically provides a button or actuator structure that can be pressed down to engage the dome during a button or key depression.

[0008] Such an arrangement is exemplified in EP 1 884 971 A1.

[0009] The formation of the button is a separate manufacturing step that is tedious and time consuming. In addition, the placement of the button relative to the dome needs to be as precise as desired and requires the provision of an additional pressing member interposed between the lateral button and the dome arrangement.

[0010] The actuating button and dome are then integrated into a housing structure with electrical connection tabs or pins, and the switch member can then be integrated into the device, for example by soldering the connection tabs or pins of the switch housing to the upper surface of a PCB (printed circuit board).

[0011] In order to simplify the structure and assembly of a dome switch, a general concept of a dome switch with an integrated actuator is proposed in US-B2-7.687.734 (US 2009 / 314619 A1).

[0012] This document proposes a dome actuator structure for use in a dome switch, the dome actuator structure having a one-piece construction, the dome actuator structure comprising a dome and an actuator element, the actuator element being attached to the dome and positioned above the dome so that depression of the actuator results in depression of the dome, and wherein the dome and the actuator are integrally formed from a metal plate.

[0013] This one-piece structure fixed (by gluing or welding) to the surface of a substrate (such as a PCB) with electrical contacts allows to obtain a switch structure without any housing structure.

[0014] However, such concepts regarding the integrated design of the dome and actuator require solutions for integrating such designs into electronic devices where: the switch needs to be actuated in various directions, including possible pre-travel; and / or the dome actuator structure needs to be industrially fixed to a substrate while maintaining the switching characteristics of the dome, including tactile feedback. Summary of the invention

[0015] The present invention provides a dome actuator structure for use in a dome switch, the dome actuator structure comprising:

[0016] - a roughly horizontal lower dome;

[0017] - an upper actuator part attached to the dome and positioned vertically above the dome such that depression of the actuator results in depression of the dome;

[0018] - and a side arm coupling the actuator portion to the dome,

[0019] The side arms and the dome are formed from a common piece of material,

[0020] The upper actuator part is an actuating block fixed to the side arm and made of a plastic material or a synthetic material or made of a natural elastomer or a synthetic elastomer.

[0021] The present invention also provides a dome actuator structure for use in a dome switch, the dome actuator structure comprising:

[0022] - a roughly horizontal dome in the lower part;

[0023] - an upper actuator part attached to the dome and positioned vertically above the dome such that depression of the actuator results in depression of the dome;

[0024] - and a side arm coupling the actuator portion to the dome, the side arm and the dome being formed from a common piece of material,

[0025] The side arms are connected to the peripheral edge of the dome by a radial connection tab, which allows the dome actuator structure to be fixed to the surface of a substrate such as a PCB by welding or gluing.

[0026] The novel features of the present invention are set forth with particularity in the appended claims.The present invention will be best understood from the following description when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a top perspective view of a dome actuator structure according to the present invention;

[0028] Figure 2 for Figure 1 A bottom perspective view of a dome actuator structure;

[0029] Figure 3 for Figure 1 An exploded view of a dome and a dome actuator structure;

[0030] Figure 4 for Figure 1 A side view of a dome actuator structure;

[0031] Figure 5 for Figure 1 A bottom view of a dome actuator structure;

[0032] Figure 6 for Figure 1 an end view of a dome actuator structure of; and

[0033] Figure 7 for Figure 1 The dome actuator structure is along Figure 5 A cross-sectional view along line 7-7. DETAILED DESCRIPTION

[0034] For the purpose of understanding the description and claims of the invention, the vertical, longitudinal and transverse orientations of the reference marks V, L, T shown in the accompanying drawings (with their longitudinal axis L and transverse axis T extending in a horizontal plane) should be adopted as non-restrictive and independent of the Earth's gravity.

[0035] In the following description, the same, similar or analogous elements or components will be denoted by the same reference numerals.

[0036] The dome actuator structure 10 shown in the drawings comprises a lower dome 12 and an upper actuator block 14 attached to the dome 12 .

[0037] Thus, the dome actuator structure 10 is a one-piece component that is secured to the upper surface 102 of the substrate 100 to provide the dome switch assembly 200 .

[0038] Figure 6 and Figure 7 A portion of a printed circuit board 100 is shown on which the dome actuator structure 10 is mounted. For example, the lower dome 12 of the dome actuator structure 10 is soldered to an upper surface 102 of the printed circuit board 100.

[0039] The lower dome 12 extends as a whole in a horizontal plane.

[0040] The lower dome 12 comprises a main central dome-shaped portion 16 oriented convexly upward and an intermediate upper apex portion 17 .

[0041] The lower dome 12 also includes four peripheral branches or arms extending radially outwardly from the central portion 16 .

[0042] Without limitation, the lower dome 12 comprises four peripheral branches distributed at angles of 90 degrees.

[0043] The four peripheral branches include two diametrically opposed longitudinally extending peripheral branches 18 and 20 and two diametrically opposed transversely extending peripheral branches 22 .

[0044] Each peripheral branch 18, 20 and 22 includes a peripheral contacting distal portion 24, 26 and 28, respectively, having a peripheral edge 30, 32 and 34, respectively.

[0045] Peripheral distal portions 24 , 26 and 28 and their peripheral edges 30 , 32 and 34 , respectively, form the periphery of lower dome 12 .

[0046] To support the upper actuation block 14 and couple it to the lower dome 12 , the dome actuator structure 10 includes side arms 36 .

[0047] The side arms 36 and the lower dome 12 are formed from a common piece of material and are integrally formed, for example, from cut and pressed metal conductive sheets.

[0048] The side arms 36 are linear and, without limitation, the side walls extend vertically.

[0049] The side arm 36 extends vertically from a lower edge 38 towards an upper free edge 40 .

[0050] Approximately two thirds of the side arm 36 constitutes an upper portion 42 of the side arm 36 .

[0051] According to the illustrated embodiment of the invention, the actuation block 14 is molded onto the upper portion 42 of the side arm 36 , which ensures the fixation and positioning of the actuation block 14 relative to the lower dome 12 of the dome actuator structure 10 .

[0052] Therefore, if Figure 7 As can be seen in FIG. 1 , the upper portion 42 of the side arm 36 appears to be received in the internal slot 44 of the actuation block 14 .

[0053] The over molding technique for attaching the actuating block 14 to the upper portion 42 of the side arm 36 is particularly suitable for mass production of dome actuator structures 10 of very small sizes, in particular by performing the molding operation of the upper portion 42 prior to the folding operation of the cut metal sheet.

[0054] According to a variation that is not shown, the actuation block 14 may be separately molded with the receiving slot 44 therein, and the upper portion 42 of the side arm 36 may be press-fitted therein.

[0055] The lower horizontal edge 38 of the side arm 36 is connected to the peripheral edge 30 of the peripheral branch 18 of the lower dome 12 by means of a bent elbow 46 and a horizontal connecting horizontal tab 48 .

[0056] A connecting tab 48 extends longitudinally between the connecting elbow 46 and the peripheral edge 30 .

[0057] The design of the connection between the lateral arm 36 and the lower dome 12 allows the lateral arm 36 to pivot relative to the lower dome 12 in two directions by elastic deformation about a lower transverse and substantially horizontal pivot axis A, primarily by elastic deformation of the bent elbow 46 .

[0058] In the drawings, the side arms 36 are shown with the dome actuator structure 10 in an undeformed state, wherein the side arms 36 extend vertically.

[0059] A horizontal connecting tab 48 extends radially in the extension of the peripheral branch 18 between the peripheral edge 30 of the peripheral branch 18 and the lower end of the lateral arm 36 .

[0060] The radial connecting web 48 has a flat, horizontal underside 50 which extends above the upper surface 102 of the base plate 100 .

[0061] This underside 50 provides an important area which provides stability.

[0062] The underside surface 50 may be used to secure the dome actuator structure 10 , for example by welding or gluing the dome actuator structure 10 to the upper surface 102 of the substrate 100 .

[0063] The distal portions 28 of the two lateral peripheral branches 22 also terminate in an overall horizontal orientation and each have a flat horizontal underside 29 that can be used to secure the dome actuator structure 10 to the upper surface 102 of the base plate 100 .

[0064] Also, in order to provide stability of the dome actuator structure 10 on the upper surface 102 of the substrate 100 , the lower dome 12 may include another radial connection tab 52 having a flat, horizontal underside 54 .

[0065] The underside 54 has a critical area which provides stability.

[0066] The underside surface 54 may be used to secure the dome actuator structure 10 , such as by welding or gluing the dome actuator structure 10 to the upper surface 102 of the substrate 100 .

[0067] A further horizontal connecting tab 52 extends radially from the distal portion 26 in the extension of the peripheral branch 20 .

[0068] The two connecting tabs 48 and 52 are therefore diametrically opposed and the four undersides 48 , 29 and 54 are coplanar.

[0069] The upper actuation block 14 is defined at least by a generally horizontal upper surface 60 , a generally horizontal lower surface 62 , and a generally convex rearward transverse surface 64 .

[0070] The upper actuation block 14 extends longitudinally and generally horizontally above the lower dome 12 from its rear end face 64 toward its arcuate front end 66 .

[0071] The rear end of the block 14 is disposed proximate to the side arm 36 and extends cantilevered over the central portion 16 of the lower dome 12 .

[0072] For example, in Figure 7 As can be seen in FIG. 1 , the lower portion of the front end or nose of the actuating block 14 is in the form of a rounded convex actuating portion 68 centered about a horizontal transverse axis.

[0073] The actuation portion 68 is positioned generally vertically above the central portion 16 of the lower dome 12 and is generally aligned with the apex 17 such that depression of the actuation block 14 results in depression of the lower dome 12 .

[0074] Such pressing causes a change in the state of the lower dome to establish contact between electrical contact traces, not shown, on the upper surface 102 of the substrate 100 .

[0075] This change of state may advantageously provide a tactile sensation.

[0076] The design of the actuating block allows the application of an actuating force thereon either entirely vertically or entirely laterally to cause its pivoting movement about the axis A, when considering Figure 7 , the pivoting movement is in a clockwise direction as indicated by arrow F.

[0077] An overall vertical actuation force may be applied to the upper surface 60 , and a lateral horizontal force may be applied to the rear end face 64 .

[0078] In the rest position and as in Figure 4 , Figure 6 as well as Figure 7 As can be seen in FIG. 6 , there is a vertical space or “air gap” 70 between the lower face 62 and the apex 17 of the lower dome 12 .

[0079] This provides a pre-travel capability prior to contact between the actuation portion 68 and the central portion 16 of the lower dome 12 .

Claims

1. A dome actuator structure (10) for use in a dome switch (200), the dome actuator structure (10) comprising: - a substantially horizontal lower dome (12); - an upper actuator part (14) attached to the lower dome (12) and positioned vertically above the lower dome (12) such that pressing the actuator part (14) results in pressing the lower dome (12); and - a side arm (36) connecting the actuator part (14) to the lower dome (12), The side arms (36) and the lower dome (12) are formed from a common piece of material, The actuator part is an actuator block (14) fixed to the side arm (36) and made of plastic material or synthetic material or made of natural elastomer or synthetic elastomer; the upper part (42) of the side arm (36) is received in the internal slot (44) of the actuator part (14).

2. The dome actuator structure (10) according to claim 1, characterized in that The actuating block (14) is molded onto the side arm (36).

3. The dome actuator structure (10) according to claim 1 or 2, characterized in that: The actuating block (14) comprises a first upper actuating surface (60) for acting on the actuating block (14) in a generally vertical downward direction, and / or a second lateral actuating surface (64) for acting on the actuating block (14) in a generally horizontal direction.

4. The dome actuator structure (10) according to claim 1 or 2, characterized in that: The side arm (36) is generally linear, and wherein the actuation block (14) is disposed at a vertical upper portion (42) of the side arm (36) and extends horizontally above the lower dome (12).

5. The dome actuator structure (10) according to claim 4, characterized in that The side arms (36) extend vertically.

6. The dome actuator structure (10) according to claim 1 or 2, characterized in that: The side arm (36) is connected to the peripheral edge (30) of the lower dome (12) by a connection (46) which allows the side arm (36) and the actuating block (14) to pivot about a lower, generally horizontal pivot axis (A).

7. The dome actuator structure (10) according to claim 6, characterized in that The side arm (36) is connected to the peripheral edge (30) of the lower dome (12) by a radial connecting tab (48).

8. The dome actuator structure (10) according to claim 7, characterized in that The one radial connecting tab (48) extends between the peripheral edge (30) of the lower dome (12) and the lower end (38) of the side arm (36).

9. The dome actuator structure (10) according to claim 7, characterized in that The dome actuator structure includes another radial connecting tab (52).

10. The dome actuator structure (10) according to claim 9, characterized in that The one radial connecting web (48) and the other radial connecting web (52) are opposed to each other in a diametrical direction.

11. The dome actuator structure (10) according to claim 9, characterized in that Each of the one radial connection tab (48) and the other radial connection tab (52) has a flat horizontal underside (50, 54) for extending over a facing portion of an upper surface (102) of a base plate (100).

12. The dome actuator structure (10) according to claim 11, characterized in that The underside of the one radial connecting web and the underside of the other radial connecting web are coplanar.

13. The dome actuator structure (10) according to claim 9, characterized in that The lower dome (12) comprises a central dome-shaped portion (16) and at least two peripheral branches extending radially and downwardly from the periphery of the central dome-shaped portion (16), and wherein each of the one radial connecting tab (48) and the other radial connecting tab (52) extends from a radial peripheral edge (30) of the associated peripheral branch.

14. The dome actuator structure (10) according to claim 13, characterized in that The lower dome (12) includes four peripheral branches extending radially and downwardly from the periphery of the central dome-shaped portion (16) and distributed at 90 degrees angles.

15. A dome switch assembly (200), comprising a dome actuator structure (10) according to any one of the preceding claims 1 to 14 and a substrate (100) having an upper surface (102), wherein the lower dome (12) is fixed to the upper surface (102) of the substrate (100) by gluing or welding.

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