User interface assembly

Abstract

A user interface assembly 3 comprises a first substrate 10, a second 30, and a third substrate 50, the second substrate being interposed between the first and third substrates. First and second conduc

Description

Field The present invention relates to a user interface assembly for use in a control panel for an electronic or electrical device. Summary According to a first aspect of the present invention there is provided a user interface assembly. The user interface assembly comprises a first substrate having first and second opposite faces, a second substrate having first and second opposite faces, first and second contact lands supported on the first face of the second substrate, the first and second contact lands formed of conductive ink, a light-emitting diode having first and second contact pads connected to the first and second contact lands respectively, a third substrate having first and second opposite faces, and first and second conductive tracks supported on the first face of the third substrate, the first and second conductive tracks formed of conductive ink. The second substrate is interposed between the first and third substrates, and the first and second contact lands are aligned with the first and second conductive tracks and the first and second contact lands, the second substrate and first and second conductive tracks are configured such that the first and second contact lands are capacitively coupled to the first and second conductive tracks respectively. The user interface assembly can be used not only for display, but also for capacitive touch sensing. Furthermore, the assembly can be fabricated by printing. The user interface assembly may further comprise a capacitive-touch pad supported on the first face of the second substrate, the capacitive-touch formed of conductive ink and a third conductive track supported on the first face of the third substrate, the third conductive track formed of conductive ink. The capacitive-touch pad may be aligned with the third conductive track such that the capacitive-touch pad is capacitively coupled to the third conductive track. The user interface assembly may further comprise a diode configured to be connected in anti-parallel to the light emitting diode. The diode may have first and second contacts connected to the second and first contact lands respectively. The lightemitting diode may be a first light-emitting diode and the diode may be a second light-emitting diode. The first and second substrates may be formed in a single piece, for example, In a single sheet then folded. The first and second substrates may be bonded or fused together. The contact lands, the capacitive-touch pad and the conductive tracks may comprise carbon and / or metallic conductive ink. The contact lands, the capacitive-touch pad and the conductive tracks may be printed using an inkjet, offset, lithographic or gravure printing process. According to a second aspect of the present invention there is provided a system comprising the user interface assembly of the first aspect and a controller comprising a first circuit for applying an alternating current signal between the first and second conductive tracks; and a second circuit for capacitance sensing of a part of the user interface assembly. The part of the user interface assembly may include the first and / or second contact land. The part of the user interface assembly may include the capacitive-touch pad. According to a third aspect of the present invention there is provided an electronic or electrical device comprising the user interface assembly of the first aspect and / or the system of the second aspect. Brief Description of the Drawings Certain embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic front view of an electronic or electrical device having a control panel which includes a front panel and indicia supported on the front panel; Figure 2 is a plan view of a portion of the control panel shown in Figure 1 having a first user interface assembly comprising a capacitive touch switch and at least one light-emitting diode; Figure 3 is a plan view of the portion of the control panel shown in Figure 2 including printed parts and components lying behind the front panel; Figure 4 is a plan view of the printed parts and components shown in Figure 3 without the front panel; Figure 5 is a plan view of some of the printed parts shown in Figure 4; Figure 6 is a cross-sectional view taken along the line A-A' in Figure 3; Figure 7 is a circuit diagram for controlling the capacitive touch switch and the at least one light-emitting diode shown in Figures 2 to 4; Figure 8 is a plan view of a portion of a control panel having a second user interface assembly comprising a capacitive touch switch and at least one light-emitting diode; and Figure 9 is a circuit diagram for controlling the capacitive touch switch and the at least one light-emitting diode shown in Figure 8. Detailed Description of Certain Embodiments Referring to Figure 1, an electronic or electrical device 1 having an integrated control panel 2 is shown. The control panel 2 includes a user interface assembly 3 which supports indicia 4. Via the control panel 2, a user (not shown) is able to control operation of the device 1, for example, which the device 1 on or off, and, optionally, enter settings. The device 1 can take the form of a consumer electronic device (such as a television), a domestic appliance (such as a washing machine, a vacuum cleaner, or heater), a vehicle (such as a car or automobile), a drone or robot, garden equipment (such as a lawn mower), a control unit (such as remote controller or home system control panel), or an industrial device (such as a controller for plant or machinery). The device 1 may be mobile or portable, semiportable or fixed. Referring to Figures 2 to 5 and Figure 6, the user interface assembly 3 comprises a multi-layer stacked structure 5. The multi-layer stacked structure 5 comprises a first substrate 10 (or "top layer") having first and second opposite faces 11, 12 (or "upper and lower faces"), a second substrate 30 (or "intermediate layer") having first and second opposite faces 31, 32 (or "upper and lower faces"). The first face 31 of the second substrate 30 supports contact lands 33, 34 supported formed of conductive ink. The contact lands 33, 34 are preferably printed directly on the first face 31 of the second substrate 30. A lightemitting diode 36 having first and second contacts (or "terminals") (not shown) is connected to the first and second contact lands 33, 34. A diode 39 having first and second contacts or terminals (not shown) may also be connected to the first and second contact lands 33, 34 anti-parallel to the light emitting diode 36. The diode 39 may also be a light-emitting diode. The contact lands 33, 34 may have an area of between 2 mm2 to 500 mm2, although they can be bigger, for example, if a contact land 33, 34 is dual-purpose and Is used as a touch-sensitive pad. The multi-layer stacked structure 5 further comprise a third substrate 50 (or "bottom layer") having first and second opposite faces 51, 52 (or "upper and lower faces"). The first face 51 of the third substrate 50 supports the first and second conductive tracks 53, 54 formed of conductive ink. The conductive tracks 53, 54 are preferably printed directly on the first face 51 of the third substrate 50. The second substrate 30 is interposed between the first and third substrates 10, 50. The first face 51 of the third substrate 50 faces the second face 32 of the second substrate 30 and the first face 31 of the second substrate 30 faces the second face 12 of the first substrate 10. Thus, the conductive tracks 53, 54 are sandwiched between the third substrates 50 and the second substrate 30, and the diode 36 and the contact lands 33, 34 are sandwiched between the second substrate 30 and the first substrate 10. The first, second and third substrates 10, 30, 50 are bonded together using adhesive (not shown) or directly, for example, by diffusion bonding. The first, second and third substrates 10, 30, 50 may be formed from a suitable plastic material, such as polyurethane (PU), polyethylene (PE), polypropylene (PP) or polyvinyl chloride (PVC). The substrates 10, 30, 50 are preferably formed from the same material to aid manufacturability, although they need not be. The thicknesses of the first and second substrates 10, 30 are sufficiently thin to allow capacitive coupling through the substrates and may be between, for example, 50 to 500 pm. The thickness of the third substrate 50 may be similar to those of the first and second substrates 10, 30. If the substrates 10, 30, 50 are sufficiently thin and flexible then the user interface assembly 3 can be manufactured using a continuous roll-based process. The first and second contact lands 33, 34 are aligned with the first and second conductive tracks 53, 54 and the first and second contact lands 33, 34, the second substrate 30 and first and second conductive tracks 53, 54 are configured such that the first and second contact lands 33, 34 are capacitively coupled to the first and second conductive tracks 53, 54 respectively. The user interface assembly 3 further comprises a capacitive-touch land 35 supported on the first face 31 of the second substrate 30 formed of conductive ink. The assembly also comprises a third conductive track 55 supported on the first face 51 of the third substrate 50 formed of conductive ink. The capacitive-touch pad 35 is aligned with the third conductive track 55 such that the third contact land 35 is capacitively coupled to the third conductive track 55. The capacitive-touch pad 35 is sufficiently large to be capacitively couplable to a user's finger. For example, it may have an area of between 10 mm2 to 1,000 mm2. Materials and dimensions (such as substrate thickness and pad area) are selected such that when a user's finger is in contact with the face 11 of the top layer 10, the capacitance between the user's finger and the capacitive-touch pad 35 is sufficient for detection, typically under a nanofarad. The coupling capacitance between contact lands 33 &conductive tracks 53 and between contact lands 34 &conductive tracks 54 may be of the order of a nanofarad or even less. The contact lands 33, 34, the capacitive-touch pad 35 and conductive tracks 53, 54, 55 comprise carbon and / or metallic conductive ink which may be printed using, for example, inkjet, offset, lithographic or gravure printing processes. Referring to Figure 7, a system 60 is shown which comprises the user interface assembly 3 and a user interface controller 61. The user interface controller 61 comprises a first circuit 62 for applying an alternating current signal between the first and second conductive tracks 53, 54 and a second circuit 63 for capacitance sensing of a part of the user interface assembly, such as the touch-sensitive pad 35. The first and second circuits 62, 63 may be controlled by a controller 64. The controller 64 and, optionally the first and second circuits 62, 63 may implemented by a microcontroller. As mentioned hereinbefore, a contact land 33, 34 may also serve as a touch-sensitive pad and so the need for a separate touch-sensitive pad can be avoided. Referring to Figure 8, a modified user interface assembly 3' is shown. The modified user interface assembly 3 is the same as the user interface assembly 3 described hereinbefore except that the capacitive-touch land 35 (Figure 3) and third conductive track 55 (Figure 3) are omitted. Referring to Figure 9, a modified system 60' is shown which comprises the user interface assembly 3' and a modified user interface controller 61'. The modified user interface controller 61' includes a multiplexer / demultiplexer 65 which switches the tracks 53, 54 between the first and second circuits 62, 63. Thus, in first mode, the driving circuit 62 drives the tracks 53, 54 to energise the lightemitting diode 36 and, in a second mode, one or both tracks 53, 54 are used for sensing. A cycle time for the first and second modes can be used which is sufficiently short that the human eye does not perceive flicker. It will be appreciated that many modifications may be made to the embodiments hereinbefore described.

Claims

1. A user interface assembly (3) comprising:a first substrate (10) having first and second opposite faces (11, 12);a second substrate (30) having first and second opposite faces (31, 32);first and second contact lands (33, 34) supported on the first face of the second substrate, the first and second contact lands formed of conductive ink;a light-emitting diode (36) having first and second contact pads (37, 38) connected to the first and second contact lands respectively;a third substrate (50) having first and second opposite faces (51, 52);first and second conductive tracks (53, 54) supported on the first face of the third substrate, the first and second conductive tracks formed of conductive ink;wherein the second substrate is interposed between the first and third substrates;wherein the first and second contact lands are aligned with the first and second conductive tracks and the first and second contact lands, the second substrate and first and second conductive tracks are configured such that the first and second contact lands are capacitively coupled to the first and second conductive tracks respectively.

2. The user interface assembly of claim 1, further comprising:a capacitive-touch pad (35) supported on the first face of the second substrate, the capacitive-touch formed of conductive ink; anda third conductive track (55) supported on the first face of the third substrate, the third conductive track formed of conductive ink;wherein the capacitive-touch pad is aligned with the third conductive track such that the capacitive-touch pad is capacitively coupled to the third conductive track.

3. The user interface assembly of claim 1 or 2, further comprising:a diode (39) configured to be connected in anti-parallel to the light emitting diode (36).

4. The user interface assembly of claim 3, wherein the diode has first and second contacts (40, 41) connected to the second and first contact lands (33, 34) respectively.

5. The user interface assembly of claim 3 or 4, wherein the light-emitting diode is a first light-emitting diode and the diode is a second light-emitting diode.

6. The user interface assembly of any of claims 1 to 5, wherein the first and second substrates are formed in a single piece.

7. The user interface assembly of any of claims 1 to 5, wherein the first and second substrates are bonded or fused together.

8. A system comprising:the user interface assembly of any one of claims 1 to 7; anda controller comprising:a first circuit for applying an alternating current signal between the first and second conductive tracks; anda second circuit for capacitance sensing of a part of the user interface assembly.

9. The system of claim 8, wherein the part of the user interface assembly includes the first and / or second contact land.

10. The system of claim 9, when dependent on claim 2, wherein the part of the user interface assembly includes the capacitive-touch pad.

11. An electronic or electrical device comprising the user Interface assembly of any one of claims 1 to 7 or the system of any one of claims 8 to 10.

Images