It is mainly made of a material with high pyroelectric coefficient, such as lead zirconate titanate ceramics, lithium tantalate, triglyceride titanium sulfate, etc. to make the detection element with a size of 2*1mm. Install one or two detection elements in each detector, and connect the two detection elements in series with reverse polarity to suppress the interference caused by the rise of their own temperature. The detection element converts the detected and received infrared radiation into a weak voltage signal, which is amplified by the field effect tube installed in the probe and output outward. In order to improve the detection sensitivity of the detector and increase the detection distance, a Fresnel lens is generally installed in front of the detector. The lens is made of transparent plastic. The upper and lower parts of the lens are divided into several equal parts. It is a kind of lens with a special optical system. It can amplify the signal by more than 70 decibels in cooperation with the amplifying circuit, so that the movement of people within 20 meters can be measured. PassiveInfrared Ray,Pyroelectric sensor,Highly sensitive sensor Dongguan XINYUDA Technology Co., Ltd. , https://www.gdxige.com
According to statistics, in 2010, China's presidential hardware imports amounted to 10.684 billion U.S. dollars, an increase of 22.6% year-on-year, of which hinged products for the main components of doors and windows increased by 47.3% in 2010 compared to 2009, indicating that China's high-end market is still occupied by foreign brands. At present, our development methods are extensive, and there is a serious surplus of backward production capacity. There are many low-grade products, and there are few high-end and middle-grade products. Some of our products are still not similar in shape, lacking core technologies, lacking independent intellectual property rights, lacking world famous brands, and lacking core competitiveness. . Unfortunately, at present, we do not have a national-level enterprise technology center in the architectural hardware industry.
Locks are an important part of the construction hardware industry. Although there are a large number of enterprises in the lock industry in China, most of them are small-scale enterprises with backward technologies, low grades of products, and poor competitiveness. Enterprises that have independent research and development capabilities and directly participate in international competition Too little, revitalizing the Chinese lock industry has a long way to go.
The Fresnel lens uses the special optical principle of the lens to produce an alternating "blind zone" and "high-sensitivity zone" in front of the detector to improve its detection and reception sensitivity. When someone walks in front of the lens, the infrared rays emitted by the human body will alternate from the "blind area" to the "high sensitive area", so that the received infrared signal is input in the form of sudden strong and weak pulses, thereby strengthening its energy amplitude .
The central wavelength of infrared radiation radiated by the human body is 9~10--um, and the wavelength sensitivity of the detection element is almost stable in the range of 0.2~20--um. A window equipped with a filter lens is opened at the top of the sensor. The wavelength range of light that this filter can pass is 7~10--um, which is suitable for the detection of human infrared radiation, and other wavelengths of infrared rays are filtered. The sheet is absorbed, thus forming an infrared sensor specially used to detect human body radiation.
Comment on the development of architectural hardware industry
Construction hardware starts with hand-made workshops such as Tiepu, coppersmiths and tinsmith shops. China had nail-making workshops in the Tang Dynasty. Hand-made nails, latches, locks, and knockers were used. However, due to the use of wood and stone structures in ancient buildings, construction hardware has developed slowly over the past few millennia. After the 19th century, with the widespread use of metal materials and the needs of social life, building hardware has been rapidly developed, and many small steel nails, hinges, latches, window hooks, tap fittings, wire braided screens, etc. have appeared. Factory or workshop. Later, it gradually adopted mechanical processing equipment instead of hand-made, forming a number of specialized companies. With the continuous improvement of various building facilities standards, modern architectural hardware products have evolved from a single species to serialization, and their aesthetic and decorative effects have become increasingly demanding. The production process of architectural hardware products has also made great progress. Most of the products have been developed from semi-manual and semi-mechanical operations into semi-automatic or fully automatic mechanical line production. Architectural hardware has been expanded from traditional copper alloys, low carbon steels, etc., to zinc alloys, aluminum alloys, stainless steels, plastics, fiberglass and various composite materials. However, the development of the construction hardware industry has also presented a series of problems.