Surface-mounted backlight switch

Abstract

A novel backlit surface mount switch for light emitting applications is disclosed. The backlight switch does not have an integrated LED or other type of lamp, but is designed to be positioned above a light source mounted on or below the PCB such that the light source is displayed by an actuator of the switch when illuminating.

Description

Surface mount backlight switch Technical Field

[0001] This application relates to surface-mount components for use on printed circuit boards (PCBs), and more specifically to surface-mount switches, and more particularly to the field of light-emitting surface-mount switches. Background Technology

[0002] PCB-mount LEDs are compact light-emitting diodes specifically designed for direct attachment to circuit boards. They are small in size and configured for attachment to PCBs via solderable pads or as surface mount components. PCB-mount LEDs are frequently used as status lights or indicator lights, or as backlights for displays, keyboards, and control panels. They are widely used in automotive, consumer electronics, and wearable technology applications. They can provide a variety of colors of light, including white light. PCB-mount LEDs are available in surface mount diode (SMD), chip-on-board (COB), and dual in-line package (DIP) devices.

[0003] Surface mount switches can be directly mounted on a PCB and are typically used for momentary actions, such as opening a device or providing a signal to a circuit to perform a specific action, such as a reset button or selecting a specific function or feature of a circuit. Surface mount switches are widely used in fields such as consumer electronics, industrial equipment, automotive applications, and medical devices.

[0004] Illuminated surface-mount switches are known in the prior art. Such switches combine an integrated LED or other type of lamp (i.e., an incandescent or neon lamp) with the surface-mount switch. Illuminated surface-mount switches can exhibit independent illumination, where the switch and lamp are electrically connected independently, or the switch and lamp can share an electrical connection. Typically, the state of the lamp is related to the actuation of the switch. Several commercially available examples of such switches are shown in Figure 1. Illuminated surface-mount switches can be covered with user interface material that displays the switch function, an example of which is shown in Figure 2. Summary of the Invention

[0005] This article discloses a novel backlight switch for light-emitting applications. Instead of having an integrated LED or other type of lamp, the backlight switch is designed to be positioned above a light source, allowing the light source to be displayed via the switch's actuator.

[0006] In various embodiments, the switch may be a surface-mount device designed to be mounted on a surface of a printed circuit board (PCB) that covers a light source. The light source may be, for example, a surface-mount LED, or the switch may cover an opening in the PCB through which light from another light source is exposed.

[0007] Because the switch does not integrate a light source, it can be manufactured at a lower cost than traditional light-emitting switches. Additionally, the operation of the light source and the switch can be completely independent. Attached Figure Description

[0008] As an example, specific exemplary embodiments of the disclosed systems and methods will now be described with reference to the accompanying drawings, in which:

[0009] Figure 1 is a schematic diagram of several commercially available prior art light-emitting surface-mount switches.

[0010] Figure 2 is a schematic diagram of an exemplary application of an LED switch.

[0011] Figure 3 is an exploded view of one embodiment of the device.

[0012] Figure 4 is a rotated perspective view of the main body of the device.

[0013] Figure 5 is a rotating perspective view of the electrical contacts of the device.

[0014] Figure 6 is a rotating perspective view of the electric actuator of the device.

[0015] Figure 7 is a rotating perspective view of the user actuator of the device.

[0016] Figure 8 is a side cross-sectional view of the device.

[0017] Figure 9 (A, B) shows two additional embodiments of the device.

[0018] Figure 10 is an electrical schematic diagram of an exemplary embodiment of the device.

[0019] Figure 11 (AC) shows the device in its in-situ configuration with various types of light sources. Detailed Implementation

[0020] An exploded view of one embodiment of device 300 is shown in FIG. 3. The body of device 300 includes a molded body 308, which may be made of a plastic material (e.g., polyamide) or any other non-conductive rigid material. A rotated perspective view of body 308 is shown in FIG. 4. Body 308 defines a recessed region 402 on its underside, the recessed region having a through-hole 404 defined therein, the through-hole penetrating body 308. The recessed region 402 is designed to receive a surface-mounted light source when the switch is mounted above a light source on a PCB. The through-hole 404 allows light from the light source to pass through the body 308 of device 300 and illuminate it.

[0021] An exemplary embodiment of the electrical contacts of the switch is shown in a rotated perspective view in FIG. 5. There are two electrical contacts 310 and 312 disposed within a body 308 and having legs 508 extending to the outside of the body 308 to allow external connection. Contacts 310 and 312 are electrically connected when the switch is actuated. Electrical contact 312 defines a central annular portion 506 that covers an aperture 404 defined in the body 308 of the device 300. The annular portion 506 defines an aperture 502 therein, which aligns with the aperture 404 in the body 308 to allow light from an external light source to pass through and illuminate it. Electrical contact 310 defines a generally semi-circular portion 504 that surrounds the annular portion 406 of contact 312 but does not physically contact the annular portion 506. Electrical contacts 310 and 312 define legs 508 that allow the device 300 to be surface-mounted to a PCB via soldering to surface-mount contact pads defined on a PCB. Electrical contacts 310 and 312 can be made of any conductive material, such as copper, gold-plated or silver-plated copper, or alloys of various conductive materials. As will be appreciated, the design of electrical contacts 310 and 312 is not limited to the embodiment shown in FIG. 5, but can be any configuration that allows electrical contact between any combination of surface-mount contact pads on the PCB, as long as the central portion of the device 300 aligned with the hole 404 in the body 308 remains unobstructed, such as not blocking light from external light sources.

[0022] Figure 6 illustrates an electric actuator 306 that makes contact between electrical contacts 310 and 312. The electric actuator 306 defines two portions: an edge 602 located on the semi-circular portion 504 of contact 310, and a flexible dome portion 604 that, when pressed from above, bends to contact the annular portion 506 of contact 312, thereby electrically connecting contacts 310 and 312. When the pressure on the electric actuator 306 is released, the dome portion 604 returns to its unbent position, breaking the contact between contacts 310 and 312. The actuator 306 defines an aperture 606 at its center, which allows light from a light source to pass through and illuminate it. The electric actuator 306 can be made of any conductive material, such as copper, gold-plated or silver-plated stainless steel, or alloys of various conductive materials.

[0023] Figure 7 illustrates a user actuator 304, which is the portion of the device 300 pressed by a user to actuate a switch. When the user presses the top portion 702 of the user actuator 304, portion 704 applies pressure to the electro-actuator 306, forcing the electro-actuator 306 to bend. This causes contact with the annular portion 506 of the contact 312, thereby establishing an electrical contact between contacts 310 and 312. When the pressure is released from the top portion 702, the electro-actuator 306 is allowed to remain bent and push the portion 704 upward, thereby breaking the electrical connection between contacts 310 and 312. The user actuator 304 defines an aperture 706 therein, which aligns with the aperture 502 in the annular portion 506 and the aperture 404 in the body 308 to allow light from an external light source to pass through and illuminate it. Preferably, the user actuator 304 is semi-rigid and is made of silicon or other semi-rigid materials, such that region 708 is capable of bending downward when pressure is applied to the top portion 702. Preferably, the user actuator 304 is transparent to allow the true color of the external light source to be visible to the user of the device 300. Alternatively, the actuator 304 may be colored to provide color to a white light source.

[0024] The device 300 is held together by a clip 302 having a portion that engages with a complementary portion on the body 308. Preferably, the clip 302 snaps into place and may be made of a rigid material, such as stainless steel. The clip 302 can be of any design and is not intended to be limited to the design shown in Figure 3. The clip 302 defines a hole at its center to allow the top portion 702 of the user actuator 304 to protrude therefrom.

[0025] Figure 8 is a side cross-sectional view of the device 300, illustrating how the previously described components interact. The edge portion 602 of the electric actuator 306 rests on the semi-circular portion 504 of the electrical contact 310. When pressure is applied to the top portion 702 of the user actuator 304, portion 704 applies pressure to the dome portion 604 of the electric actuator 306, causing the dome portion 604 to bend and contact the annular portion 506 of the electrical contact 312, thereby electrically connecting contacts 310 and 312. When pressure is released from the top portion 702 of the user actuator 304, the dome portion 604 of the electric actuator 306 does not bend, causing the dome portion 604 to lose contact with the annular portion 506 of the electrical contact 310, thereby disconnecting the electrical connection between contacts 310 and 312. The contact between the dome portion 604 of the electric actuator 306 and the portion 704 of the user actuator 302 keeps the top portion 702 of the user actuator 304 extended and in a pushed position.

[0026] Figure 9A illustrates an additional embodiment in which a transparent adhesive film or resin 902 seals the interior of the device 300. The function of the film 902 is to ensure a relative seal between the switch and the water / dust. The film 902 may rest on a flange 406 defined in a recess 402 of the body 308. Figure 9B illustrates yet another embodiment in which a lens 904 is positioned in a hole 404 defined in the body 308 and may extend through the hole 502 defined in an annular portion 506 of the electrical contact 312. The lens 904 may be shaped to match the shape of the annular portion 506 of the electrical contact 312. The purpose of the lens 904 is to focus light from an external light source onto the interior of the user actuator 304 so that it is visible to the user from the top portion 702. The lens 904 may also be used without the film 902. In various embodiments, the lens 904 may be made of optical resin or optical glass.

[0027] Figure 10 is a schematic diagram of the circuitry in device 300. In the exemplary embodiment described herein, when the switch is actuated, legs 508(1) and 508(2) defined on electrical contact 310 are electrically connected to legs 508(3) and 508(4) defined on electrical contact 312. Other embodiments are possible in which other combinations of legs 508(1-4) are electrically connected to the activation device 300.

[0028] Figure 11(AC) shows a cross-sectional view of device 300 and PCB 1102, illustrating device 300 mounted in situ on a PCB with various types of light sources. Figure 11A shows a surface-mount LED 1104, wherein LED 1104 is received in a recess 402 of body 308. This figure shows a lamp 1110 shining upward through the top portion 702 of user actuator 302. Figure 11B shows a configuration similar to that of Figure 11A, in which the light source is an LED film 1106. Figure 11C shows the use of device 300, wherein the light source is located below the PCB board, and wherein light is transmitted through holes in the PCB or via a light tube 1108 that extends through PCB 1102 and may enter the recess 402 of body 308.

[0029] In various embodiments, the dimensions of the device 300 and its components can vary, and the materials used to construct the components can also differ. In one embodiment, the device 300 measures 6.2 mm x 6.2 mm x 3.5 mm. The total stroke of the user actuator 302 is approximately ±3.5 mm, requiring an activation force of ±1 N - 4 N. The diameter of the electric actuator 306 is ±5 mm. The body 308 and the lens 904 can be constructed from the same or similar materials, such as a white translucent material. The device 300 is expected to have a lifespan of approximately 500,000 cycles.

Claims

1. An apparatus comprising: A body defining a recessed area and a through hole, the through hole communicating with the recessed area and extending through the body; A first electrical contact and a second electrical contact are disposed within the body; an electric actuator having a generally dome shape and defining a hole at its center, the hole being aligned with a through hole defined in the body, the electric actuator contacting one of the first electrical contact and the second electrical contact. And a user actuator disposed above the electric actuator; wherein pressure applied to the user actuator causes the electric actuator to bend and contact the other of the first and second electric contacts, thereby establishing an electrical contact between the first and second electric contacts.

2. The apparatus according to claim 1, further comprising: A clip having a hole defined at its center through which a top portion of the user actuator extends; wherein the clip is made of a rigid material and defines one or more portions that engage with complementary portions defined on the body.

3. The apparatus according to claim 1, wherein, The device is a surface-mount switch, and further, a recessed area defined in the body covers the light source when the switch is mounted on a printed circuit board.

4. The apparatus according to claim 3, wherein, The recessed area is sized and shaped to receive a surface-mount light source when the switch is mounted on the printed circuit board.

5. The apparatus according to claim 1, wherein, The first electrical contact defines a generally semi-circular portion, and further, the electrical actuator contacts the semi-circular portion.

6. The apparatus according to claim 5, wherein, The second electrical contact defines an annular portion disposed within, but separate from, the semicircular portion of the first electrical contact, the annular portion defining a hole at its center, the hole being aligned with a through hole defined in the body and a hole defined in the electric actuator.

7. The apparatus according to claim 1, further comprising: A transparent film or resin covering the through-holes defined in the body.

8. The apparatus according to claim 6, further comprising: A lens is disposed between the body and the second electrical contact.

9. The apparatus according to claim 8, wherein, The lens extends through a hole defined in the annular portion of the second electrical contact.

10. The apparatus according to claim 8, further comprising: A transparent film or resin covering the through-holes defined in the body.

11. The apparatus according to claim 1, wherein, The user actuator is transparent and made of a rigid material.

12. The apparatus according to claim 11, wherein, The user actuator is made of silicon.

13. The apparatus according to claim 1, wherein, The electric actuator and the first and second electrical contacts are made of gold, copper, or various alloys thereof.

14. The apparatus according to claim 1, wherein, The first and second electrical contacts each define one or more leg portions extending through the body.

15. The apparatus according to claim 14, wherein, The support leg section enables the device to be soldered to a printed circuit board.

16. The apparatus according to claim 1, wherein, The body is made of a rigid, non-conductive material.

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