How does the stainless steel automatic infrared sensing soap dispenser use the Fresnel lens?

The stainless steel automatic infrared induction soap dispenser achieves accurate recognition and rapid response to the user's hand movements by utilizing the focusing effect of the Fresnel lens, improving sensitivity, reducing false triggering, and being lightweight, efficient and cost-effective.

Basic principle of Fresnel lens: Fresnel lens, also known as infrared focusing lens, is a special lens that works in the infrared wavelength range. It consists of a series of concentric ring structures, each of which is designed to have different amplitudes and phase delays to achieve focusing and modulation of the incident infrared light. When infrared light passes through the lens, light of different wavelengths will be refracted and interfered to different degrees, forming a clear infrared image on the focal plane.

Application in stainless steel automatic infrared induction soap dispenser:
Focusing effect: One of the main functions of the Fresnel lens is focusing. In the soap dispenser, it focuses the infrared radiation emitted by the human body (especially the hands) into a smaller area, usually the sensor of the soap dispenser. By focusing, the Fresnel lens increases the sensitivity of the sensor to infrared radiation, thereby ensuring that the user's hand movements can be accurately recognized even at a longer distance or in low light conditions. Due to the focusing properties of the Fresnel lens, it is only sensitive to infrared radiation in a specific area (i.e. the area in front of the sensor), thus reducing false triggering due to background infrared radiation or other interference sources.