Rotational angle and speed detection via a chip-scale GaN optoelectronic device

Area of Science:

• Optoelectronics
• Microfabrication
• Sensors

Background:

• Accurate rotational angle and speed measurement is crucial for various industrial applications.
• Existing sensing systems can be costly, bulky, or lack efficiency.
• Advancements in optoelectronic chip technology offer potential for improved sensor design.

Purpose of the Study:

• To propose a new method for rotational angle and speed measurements.
• To develop a sensing system by integrating a Gallium Nitride (GaN) optoelectronic chip with a novel stepped disc.
• To evaluate the performance and efficiency of the developed sensing architecture.

Main Methods:

• Fabrication of an optoelectronic chip integrating a light-emitting diode (LED) and photodiode (PD) using wafer-level microfabrication.
• Design of a disc with a spiral staircase shape and increasing thickness distribution.
• Measurement of angle-dependent light intensity changes reflected off the stepped disc by the optoelectronic chip.

Main Results:

• The developed system demonstrates high sensitivity for continuous rotation from 0° to 360°.
• Photocurrent generation accurately indicates both rotational angle and speed.
• Rotational speeds up to 5000 rpm were measured with a relative error below 1.27%.

Conclusions:

• The integrated GaN optoelectronic chip and stepped disc system offers a viable new method for rotational sensing.
• This sensing architecture provides a low-cost, miniaturized, and high-efficiency solution.
• The system has potential applications in various fields requiring precise rotational monitoring.