Thermal Model and Countermeasures for Future Smart Glasses

Area of Science:

• Wearable technology
• Thermal engineering
• Human-computer interaction

Background:

• The wearable technology market, especially smart glasses, is rapidly expanding.
• Smart glasses offer augmented reality (AR) but pose thermal challenges due to facial contact.
• High device temperatures can negatively affect user physical health and comfort.

Purpose of the Study:

• To develop a thermal network model for steady-state analysis of smart glasses.
• To propose and evaluate thermal countermeasures for effective thermal management.
• To ensure user safety and enhance the experience of wearing smart glasses.

Main Methods:

• Deconstructing smart glasses into thermal network components.
• Modeling heat-generating integrated circuits (ICs) as simplified structures.
• Calculating heat transfer coefficients for natural convection in air.
• Validating the thermal network model against a commercial thermal solver.

Main Results:

• The thermal network model showed an average temperature difference of 0.9 °C compared to a commercial solver (max temp 62 °C).
• Distributing heat sources reduced ear-contact temperature by 51.4%.
• Relocating high-power ICs decreased temperature by 11.1%; using mixed-conductivity materials reduced it by 65.3%.

Conclusions:

• The developed thermal network model accurately predicts smart glass temperatures.
• Effective thermal management strategies, including heat source distribution and material selection, can significantly mitigate heat buildup.
• These findings are crucial for designing comfortable and safe future smart glasses.