This invention relates to a membrane touch switch control panel assembly for appliances with glass control panels.
Use of glass control panels for appliances such as ranges and wall ovens is well known. Such appliances typically have electromechanical controls with user manipulated control knobs projecting through holes in the glass. Such structural arrangements are inconvenient to clean and also allow soils to enter the area behind the control panel leading to an unsightly appearance and possibly contaminating the control circuitry.
In some instances capacitive touch panel arrays have been used in lieu of mechanical knobs and switches, enhancing appearance and cleanability. Such arrays can be fabricated directly on the glass panel which serves as the dielectric substrate, thereby providing a smooth surface with no openings to collect food soils and a modern high tech appearance. Also such arrays can withstand the relatively high temperature environment to which range and oven controls are exposed. Capacitive touch switch arrays have been found to provide satisfactory performance and pleasing appearance. However, capacitive touch panels while mechanically simple are electrically relatively complex and have a relatively high system cost. Consequently, such controls generally are provided only on expensive appliances positioned at the high end of the model line.
Membrane touch switch arrays, which have substantially less system cost than capacitive touch pad arrays, are used in refrigerator, dishwasher, microwave ovens, and laundry appliances which provide a less harsh temperature environment, since materials conventionally used in membrane touch switch arrays do not tolerate high temperatures well.
Therefore, a touch control panel for appliances which has the cost advantages of membrane switch panels and the appearance and temperature tolerance advantage of capacitive touch control arrays would be highly desirable.
It is therefore a primary object of the present invention to provide a membrane touch switch control panel assembly for an appliance which provide the appearance and cleanability and temperature tolerance benefits of a capacitive touch panel array.