Yesterday the US Patent & Trademark Office published a patent application from Apple that relates to electronic devices such as an iPhone, iPad and Apple Watch with enhanced accuracy of touch input detection when the touch input display (or a transparent layer covering the touch input display) is wet.

Apple notes that a device like Apple provides Touch input technology may include multiple electrodes that form several capacitors that define an electrostatic field. When a user touches a region of the touch input display, the electrostatic field is altered, as determined by a change in capacitance, in that region. The electronic device can determine the location of the user's touch input based on the capacitance change.

The touch input display provides a dynamic user input that can alter the display. However, the performance of the display decreases when water is present. For instance, water can alter the electrostatic field by providing an electrical ground to the display. Some electronic devices deactivate the touch input component under these circumstances. Other electronic devices generate a false positive by inaccurately determining a touch input.

Alternatively, ungrounded water on the display may cause the touch input display to be non-responsive to a touch input from a user. In either event, the touch input capability of the electronic device is limited to other input mechanisms, such as buttons.

Apple's granted patent specifically describes an Apple Watch with a new transparent layer. The display assembly may include a touch input component configured to receive a touch input at the transparent layer. The touch input component is capable of determining whether a liquid is in contact with the transparent layer. The wearable electronic device may further include a force detection assembly configured to determine an amount of force applied to the transparent layer from the touch input. The force detection assembly is capable of determining a first location of the touch input.

In Apple's patent FIG. 6 below we see a plan view that partially shows an Apple Watch (#100) with liquid droplets (#142a/b/c/d) partially covering the transparent layer #106. Traditionally, water droplets could be falsely read as user input. To get around this, Apple's patent discusses the use of 'Force Touch' being used on the Apple Watch transparent layer illustrated in patent FIG. 7.

Apple's patent FIG. 21 below illustrates a block diagram of an electronic device (Apple Watch #800) showing several inputs and associated outputs generated based on the inputs used to locate a touch input to Apple Watch. The inputs and associated outputs may enable Apple Watch to locate a touch input to a display assembly #808, including instances in which a touch input component #832 of the display assembly detects liquid #803 (which may include one or more liquid droplets).

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Apple further notes that the force detection assembly may include one or more (modular) force detection units. When multiple force detection units are used, a difference in detected capacitance among the force detection units may result from a touch input, and the difference is used to determine the location of the touch input. The electronic device can use the location information from the force detection assembly to determine the location of the touch input, even when the electronic device deactivates the touch input component due to the detected presence of liquid.

For more details, review Apple's patent application number 11,422,689. For the record, While this invention was originally filed for in 2018, there's no record of a patent application publicly published for it. Apple's first public record of this invention is in the form of this granted patent.