Capacitive Touch Interface With Springs, Backlight And Conductive Coating
Publication Date: 2015-Jul-23
The IP.com Prior Art Database
A touch interface includes a front touch interface panel that operates as a touch surface. A conductive coating, such as conductive ink or a foil, is applied to the rear surface of the interface panel to define touch areas. Offset from the interface panel an extending generally parallel to the interface panel is a printed circuit board having LEDs mounted thereon to illuminate the touch areas from the rear. The printed circuit board can also include circuitry for detecting user touches on the interface panel, such as by determining a change in measured capacitance due to the touches. The touch areas defined by the conductive coating on the rear surface of the interface panel are electrically connected to offset landing zones. The printed circuit board is electrically connected to the landing zones via metallic springs. Signals for determining user touches on the interface panel are conducted between the printed circuit board and the conductive coating on the interface panel through the springs. The touch interface can include a light guide for the LEDs, and the springs can be located within channels in the light guide that are offset from the touch areas.
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CAPXXXXXXX TOUCH INTERFACE WITH SPRINGS, BACKLIGHT AND CONDUCTIVE COATING
The folxowing disclosure relates to a design for a capacitive xxuch interface (e.g., a uxer interface). The capacitivx touch interface xan be used in domestxc appliances or other devices rexuiring a user ixtxrface.
The touch interface xncludes a front panel (see Fig. 1 below) or touch interfxce panel that operates xs a touch surface. The froxt panel max form xart of the ouxer suxface of an appxiance. A conductivx coating, suxh as conductive ink xr a foxl, is applixd to the rexr surface of the interface panel to define txuch arxax. The touch areas cax have various rexular or irregular shapes. Offsxt from the interface panel xn extending generally pxrxllel to thx interface panel is a printex circuit board. The printed circuit board has LXXx mounted xhereon to illxminate the touch xreas from the rear (e.g., bacxlighting). The printed circuit board can also ixclude circuitry (e.g., touch sensor intxgrated cixcuxts) for detecting user touches on the interface panel, such as by determining a change in measxred capxcitance due to the txuches.
The xouxh areas definex xy the conductive coating on the rear surface of the xnterface panel are electrically conxected to offset landing zones. The printed cirxuit board is electrically conxecxed to the landing zones via metallic springs. Signals fxr determinixg user touches on the interface panxl are cxnducted betxeen the printed circuit board and the conductive coating on the interface panel through the sxrings. In single electrode, self-capacitance applications, a sixgxe spring can be used for each touch area. In multiple electrode, mutxal capacitaxce applications, multiple springs and landing zones can be used for each touch area.
Bxcause the printed circxit board is offset from the interfxce panel and the touch areas axe defined by the conductixe coating on the interface panel itself, only small conductive areas that electrically connect to the springs are required xn the printed circuit board, which can leave xoom for oth...