The Apple Watch Digital Crown took a huge leap forward with the release of Apple Watch Series 4 by allowing the Digital Crown to have a touch surface and ability to measure an ECG that generates an ECG waveform on the Apple Watch display as noted below.  One of the two patents that were published this week by the U.S. Patent and Trademark Office also describes the zoom feature that the enhanced crown enabled. It's very rare that patents on a product already in the market for two years finally surfaces. Obviously, Apple wanted to keep their inventions as secretive as possible and for as long as possible.

1. Conductive Cap for Watch Crown

Apple's first patent regarding the new 2018 Apple Watch Digital Crown focused on the Conductive Cap. Apple's invention describes the crown assembly  which includes a user-rotatable crown comprising a conductive cap, a crown body at least partially surrounding the conductive cap, and an isolating component positioned between the conductive cap and the crown body. The crown assembly further includes a shaft extending through an opening in the housing and mechanically and electrically coupled to the conductive cap. A processing unit of the electronic watch is coupled to the conductive cap by the shaft and is operable to determine a biological parameter of a user based on a voltage at the conductive cap.

In some embodiments, one or more additional electrodes besides the conductive cap may be positioned on the exterior surface of the electronic device. Providing electrodes on different surfaces of a device may make it easier for a user to place different body parts in contact with different electrodes. In some embodiments, for example, the conductive cap is operable to be contacted by a finger of a user of the electronic device while another electrode is positioned against skin of the user. For example, a user may place one or more of the additional electrodes in contact with their wrist, and may touch the conductive cap (or another electrode) with a finger of their opposite hand (e.g., an electronic watch may be attached to a wrist adjacent one hand, and the crown may be touched with a finger of the opposite hand).

The conductive cap and/or the additional electrode(s) may sense voltages or signals indicative of one or more biological parameters of a user who is in contact with the conductive cap and/or the additional electrode(s). As discussed above, the shaft may electrically couple the conductive cap to a processing unit or other circuit of the electronic device. One or more electrically transmissive elements may couple the additional electrode(s) to the processing unit or other circuit of the electronic device.

The processing unit of the electronic device, or a processing unit remote from the electronic device, may determine, from the voltages or signals at the electrodes (e.g., from stored digital samples or values representing the voltages or signals), the biological parameter(s) of the user.

The biological parameter(s) may include, for example, an electrocardiogram (ECG) for the user, an indication of whether the user is experiencing atrial fibrillation, an indication of whether the user is experiencing premature atrial contraction or premature ventricular contraction, an indication of whether the user is experiencing a sinus arrhythmia, and so on.

Apple's patent FIG .1B illustrates and Apple Watch that incorporates a crown assembly; FIG. 3C shows a partial view of the new crown assembly with the conductive cap removed; FIG. 8 shows an elevation of a watch body capable of sensing a biological parameter.

Apple's patent application 20200064774 was published Thursday by the U.S. Patent Office. For those that are simply curious or engineers who love details, check out Apple's full patent application here. 

Patently Apple covered an Apple patent back in 2016 that described an ECG as a feature on a device that could measure "Electrocardiographic Signals."  

For the record while the filing date on this week's patent is shown to have been made 3 months after the Apple Watch series 4 with its new Digital Crown came to market, Apple notes that the filing incorporates the benefits of an August 2018 Provisional Patent unpublished in August 2018 and going back earlier when they filed it. Obviously, Apple tried and succeeded in keeping this invention secretive until the product was into the market for some time before it was published by USPTO.

Definition: A provisional patent application, in the United States, is a mechanism through which an inventor may file a preliminary, incomplete application with the U.S. Patent and Trademark Office (USPTO) to secure a filing date which may later be relied upon in a priority claim in a regular patent application. Following this, the inventor may disclose their invention to others although the document itself will be maintained confidentially by the Patent Office unless later relied upon in a priority claim in a regular or non-provisional patent application.

2. Watch Crown having a Conductive Surface

Apple's second Apple Watch invention covering the Digital Crown with a conductive surface covers different ground than the first patent application covered above. It's a more technical patent describing new components of the Digital Crown not mentioned in the first patent.

Apple notes that the electronic watch includes an enclosure defining an opening and a crown extending through the opening and configured to receive a rotational input and a translational input.

The crown includes an inner crown body defining a conductive surface and an outer crown body at least partially surrounding the inner crown body. The crown further includes an isolator positioned between the inner crown body and the outer crown body and electrically isolating the inner crown body from the outer crown body. The crown further includes a retainer coupling the inner crown body to the outer crown body and securing the isolator between the inner crown body and the outer crown body.

While this patent definitely covers a biological parameter, such as a heart rate, an electrocardiogram, the patent also covers Digital Crown being used in connection with a zoom operation for viewing photos.

Apple's patent FIGS. 3A to 3C are examples of a crown with a conductive inner crown body be used to perform an electrocardiogram measurement or receive other touch inputs. The inner crown body #332 is electrically isolated from the outer crown body #324 by an isolator #328 positioned between the outer crown body and the inner crown body; In FIG. 4C, the head portion #432a may define a portion #482 of the external surface of the crown that defines a conductive surface for receiving touch inputs.

Apple's patent FIGS. 8A and 8B Illustrate a digital crown used to perform a zoom operation.

Apple's patent application 20200064779 was published Thursday by the U.S. Patent Office. For those that are curious or engineers who love details, check out the full patent application here.  

While the filing date is shown to have been made 4 months after the Apple Watch series 4 with its new Digital Crown came to market, Apple notes that the filing incorporates the benefits of two Provisional patents filed in August 2018, a month prior to the new Series 4 Apple Watch debuted.