The control element for sensing the human body is a pyroelectric infrared sensor, a component that detects the change of the infrared energy of the human body radiation in a non-contact manner, and uses the characteristic of temperature change to detect the infrared radiation, thereby detecting the proximity of the human body .
The pyroelectric infrared sensor only allows the infrared light of a specific wavelength range to pass through, in other words , it only acts on the human body or the body temperature approximating the human body, and "lights out" the light, sunlight and other infrared radiation, what small animals The mobile phone's electromagnetic field, lighting, etc. will not interfere with its sensing.
The pyroelectric infrared sensor is the "eye", and the Fresnel lens is the "eyeglass" of the sensor.
In the process of pyroelectric infrared sensor sensing infrared energy change, the pyroelectric infrared sensor itself is not "accurate", "Fresnel lens", which plays a vital role in the "human motion sensing" process. The role.
One is focusing, effectively concentrating the infrared rays of the detection space onto the sensor, and limiting the peak wavelength of the incident light to the range of the infrared radiation of the human body. The sensor's detection radius is less than 2 meters without the use of a Fresnel lens, and the sensor has a detection radius of up to 12 meters with a Fresnel lens.
The second is to divide the detection area into a number of bright areas and dark areas, so that moving objects/persons entering the detection area can generate varying pyroelectric infrared signals on the pyroelectric infrared sensor in the form of temperature changes. When there is no human body moving in the detection area, the pyroelectric infrared sensor senses only the background temperature. When the human body enters the detection area, the pyroelectric infrared sensor senses the difference between the human body temperature and the background temperature. After the signal is collected, it is already in the system. The existing detection data is compared, and it is judged whether or not someone actually waits for an infrared source to enter the detection area.
In the research and development and production of Fresnel lens, Shandong Yuying has been focusing on the production and research and development of Fresnel lens since 1992. It is one of the professional Fresnel lens production and supply companies.
Compared with other lenses, Fresnel lens has the advantages of small size, light weight and compact structure. It has good concentrating and imaging performance and is highly economical, so it is used in smart home, security, projector, LED lamps, solar power and other industries have been widely used.
From the shape, the Fresnel lens is divided into a plane and a spherical surface. In the case where the caliber and aberration are not strict, the Fresnel lens generally adopts a planar structure because of convenient processing.
The spherical Fresnel lens solves the problem of uneven sensitivity caused by the change of focal length. Through precision machining, the focal lengths of the detected objects at different distances are equal. The angle of Fresnel lens produced by Shandong Yuying can be expanded to 180 degrees, completely avoiding the detector. The problem of dead angle directly below.
Functionally, the Fresnel lens has a wide-angle and curtain type, and the Fresnel lens of the curtain-type infrared detector is designed to be arranged in a zigzag manner in a vertical arrangement, and the angle of detection is small, and the wide-angle infrared detector is The Fresnel lens is circularly cut into a small piece and a small piece of a multi-view multi-view area which is regularly arranged, and the more the viewing area, the larger the angle of detection.
Now we use the Fresnel lens on the market. The focal length of each layer, including the size and shape, is different. Due to the different angles, distances and shapes, the Fresnel lens is designed to meet the customer's requirements. Shandong Yuying will be customized according to customer requirements.