Nintendo’s patents for the Nintendo Switch have been found, and they hide some interesting secrets. Most importantly, it shows that Nintendo has in fact been working on a VR headset for the Switch. In the patent, it says:

The information processing system [tablet] may include an accessory to which the main unit 2 can be attached. An HMD accessory to be described below as an example accessory can be used as a so-called HMD (head mounted display) with the main unit 2 [tablet by itself] attached thereto.  FIG. 60 is a diagram showing an example HMD accessory to which the main unit 2 can be attached. […] With such a configuration, a user can view images on the display 12 when the HMD accessory 230 with the main unit 2 attached thereto is mounted on the head of the user. That is, the HMD accessory 230 with the main unit 2 attached thereto functions as a so-called HMD. Note that the HMD accessory 230 may present images of a wide viewing angle to a user by enlarging the viewing angle of the images on the display 12 through the lenses. This can enhance the sense of immersion for a user looking at the images. Note that the main unit 2 may perform a predetermined conversion process on the images displayed on the display 12 so that appropriate images are viewed through the lenses. Note that in the present embodiment, the main unit 2 includes the acceleration sensor 89 and the angular velocity sensor 90, and can calculate the movement and/or the attitude of the main unit 2 based on the detection results of these sensors. […] In the present embodiment, since the controllers can be removed from the main unit 2, it is possible to reduce the weight of the device or devices to be mounted on the head of the user. A user can perform operations using removed controllers.

In case all that legal speak confused you (I know it confused me), here are some bullet points:

• Nintendo is developing a VR headset for the Switch
• You take the Joy-Cons off to use as controllers for the headset
• The tablet tracks head movement, while the joy-cons track hand movement

Nintendo also showed a sample of the VR headet, seen below:

The patent itself is quite big, and might hold even more secrets about Nintendo’s upcoming console. If anything else is revealed, we’ll be sure to update with more info.