CROSS-REFERENCE TO RELATED APPLICATION

This application is a 35 U.S.C. § 371 National Phase Application of PCT Application No. PCT/CN2017/072634 filed Jan. 25, 2017, entitled “STEPPER MOTOR FOR USE IN ROTARY CONTROL ASSEMBLY OF INPUT DEVICE,” which is assigned to the assignee hereof and hereby expressly incorporated by reference herein for all purposes.

FIELD

Embodiments of the subject matter described herein generally relates to an electrical device, and more particularly, to a stepper motor for use in a rotary control assembly of an input device.

BACKGROUND

Among various input devices, mouse is widely used for facilitating the location of a cursor at a target position or scrolling the content of a document displayed on a webpage, for example. In additional to several buttons (such as, the left click button and right click button), most mice are also provided with a wheel (also called a roller or a thumbwheel). A wheel can be scrolled by a user's finger, and rotation of the wheel is subsequently measured and converted to various input signals to realize scrolling, zooming and other operations to the content on the display. As one of the most commonly-used input devices, mouse especially the wheels thereof have a direct impact on the operation efficiency and user experience. Other types of rotary control assembly, such as volume control and thermostat control, due to similar rotary mechanism, may face similar challenges and thus need to be improved.

SUMMARY

Embodiments of the subject matter described herein provide a stepper motor for use in a rotary control assembly. The stepper motor includes a shaft, a magnet for generating a first magnetic field, and a first coil arranged on a rotational path of the magnet. The magnet is coupled to the shaft and operable to rotate with a rotation of the shaft. The stepper motor further includes a first current source which is configured to supply a first current to the first coil to trigger the first coil to generate a second magnetic field. A main direction of the second magnetic field is substantially parallel with a main direction of the first magnetic field while the magnet rotates and passes the first coil.

Based on the interaction between the first magnetic field and the second magnetic field, a so-called “detent” will be created between the magnet and the detent coils (also referred to as the first and second coils) in opposition to the rotational direction of the rotating part, such as a wheel of a mouse or a knob of a volume control, which will in turn provide a haptic feedback back to the user who is scrolling the rotating part. Furthermore, with a flexible design and arrangement of such detent coils, along with controlled and variable detent currents provided by the current source according to embodiments of the subject matter described herein, numerous and even complicated haptic feedbacks or “feels” can be achieved according to the requirements.

It is to be understood that the Summary is not intended to identify key or essential features of implementations of the subject matter described herein, nor is it intended to be used to limit the scope of the subject matter described herein. Other features of the subject matter described herein will become easily comprehensible through the description below.

