Challenges in Protecting Accessory Inventions

Patent practitioners frequently encounter unique challenges when attempting to protect accessory inventions used by end consumers in conjunction with other products. These inventions, sold separately from the primary products they enhance, present a complex scenario for patent protection. On particular difficulty lies in claiming the accessory in a way that highlights its innovative features while avoiding the pitfalls of divided infringement and intended use claim elements.

A recent case involving ZAGG, a company known for its protective cases that include keyboards, brings these challenges to the forefront. ZAGG sought patent protection for an accessory device—a case designed to work with a keyboard. Appeal 2023-001948, Application 14/163,959 The claim language focused on an accessory for an independently available and independently operable mobile computing device. Claim 1 on appeal is reproduced below:

1. An accessory for an independently available and independently operable mobile computing device, comprising:
a base comprising a protective accessory for a display of the independently available and independently operable mobile computing device;
a coupling element associated with the base and comprising an elongated slot that removably receives an edge of the independently operable mobile computing device to orient and support the independently available and independently operable mobile computing device in a working arrangement with the base, the display of the independently available and independently operable mobile computing device being readily accessible to a user in the working arrangement;
a keyboard carried by the base;
keyboard electronics carried by the base and enabling use of the keyboard as an input accessory for the independently available and independently operable mobile computing device.

FIG. 20 from the application illustrates an example case below:

A problem arose because the claims were intended to be limited to the case/accessory itself, but the arguments against the cited prior art drifted into differences between what coupled with the case. Despite efforts to incorporate unique features, these were deemed too generic to limit the claims effectively. This case underscores the challenge of protecting an accessory on its own, without relying on its use with another product.

Specifically, in the ZAGG case, the protective case featured innovative aspects intended to enhance functionality when paired with an “ independently available and independently operable mobile computing device,” such as a tablet. However, since the tablet was a separate product, ZAGG had to consider the claims carefully as to how such a feature might be included so as to reduce the potential for divided infringement. Their attempts in claim 1 ultimately fell short because the claimed features were either deemed intended use, or were too generic to provide a clear distinction from the cited art, which as a more conventional display unit and base unit that were designed to operate together. From the PTAB’s decision (citations omitted):

First, claim 1 is directed to an accessory. The display device need not be present to meet claim 1’s structural requirements. That the accessory is “for an independently available and independently operable mobile computing device” reflects an intended use of the accessory. … Second, because claim 1 is directed to the accessory only and the accessory does not include the display device, the details of the display device are not particularly relevant beyond providing evidence that Fish’s elongated slot has the structure capable of receiving a display device such as a mobile computing device in the manner required by claim 1. …Third, even if the operability of the display were relevant, there can be no real doubt that Fish’s elongated slot has structure capable of performing the function of receiving an edge of an independently operatable mobile computing device in the manner required. … Fourth, the language “independently available” does not exclude the use of Fish’s tablet in the elongated slot of Fish’s base. Nor does that language structurally distinguish claim 1’s elongated slot from Fish’s elongated slot. Fifth, as to the word “accessory,” Appellant has not provided evidence
supporting the contention that Fish’s base unit is not an accessory within the meaning of claim 1. As we explain above, Fish’s tablet can function without the base unit, i.e., it is independently operable. Fish’s base is not essential to the tablet. Thus, the base unit merely adds functionality, such as a keyboard, and is an accessory.

This outcome highlights the difficult of crafting claims that robustly protect the accessory itself by including sufficient specificity of the accessory structure and without depending too heavily on its interaction with other products. What strategies do you use to protect accessory innovations?