The touch switch is an intelligently controlled wall switch, which itself needs to consume a certain amount of power. In standby, the standby power of the single-fire intelligent switch is to supply power to the intelligent wall switch control circuit through the current flowing through the electronic ballast. If the standby input current is small, the standby circuit will not work. If the standby input current is large, it will cause problems such as cold flashing and red filament after the electronic ballast is turned off. At work, because the single-fire smart switch is working, the power is taken through the pressure difference between the two ends when the switch is open. When the switch is closed, there is no pressure difference and no power can be taken, which will cause the control circuit to open. Loss of power and control problems. Therefore, the technical problem of single-fire-wire touch switch taking power has always existed. The development of micro-power single-fire-wire standby and working power supply circuits is very difficult. So far this is still the main technical bottleneck restricting the development of single-fire-wire touch switches at home and abroad.
Realizing a true capacitive-sensing touch switch requires a stable single live wire power supply processing and a stable and reliable touch sensor chip to prevent false triggering, prevent various electromagnetic interference, load interference, environmental interference, and even need smart touch such as waterproof and dustproof functions Switch function requirements, system solutions with integrated sensor touch function are even more technical problems in the industry.
Test method for stability of touch-sensitive panel
Keywords: touch sensing, malfunction, reliability test.
introduction:
The touch-sensitive operation panel is quickly applied in many fields because of its sturdiness, wear resistance, insulation, dust and water resistance, and beautiful appearance. It has become a popular technology. However, many products using touch-sensitive panels have encountered difficulties in production and debugging, unstable operation of touch-sensitive panels, and prone to malfunction in a humid and strong interference environment, causing problems for customers to return products.
problem:
Production debugging is difficult, and mass production is impossible. The touch-sensitive panel works unstable. In a humid, strong interference environment, it is easy to malfunction, causing customers to return the goods. The long-term work stability of the product is poor, and the product that has been debugged on the production line will increase the after-sales cost due to the sensitivity change or frequent misoperation after transportation or long-term work.
These reasons have caused many manufacturers to not only hope to adopt this new technology, but also have doubts about whether the products adopting this technology can work stably. Because the simple trial of the touch-sensitive panel often fails to find out what is wrong. It is often necessary to wait until the customer has used it for a period of time after delivery before all kinds of problems appear. At this time, it will inevitably bring cost and reputation loss to the manufacturer.
The outstanding problem that customers encounter with touch-sensitive panels is that sensitivity and reliability (no malfunction) are difficult to maintain stability in various environments, especially for long-term work.
problem analysis:
The mainstream technology of touch-sensing panels is realized by using capacitive sensing technology. Because the capacitance change brought by the finger on the sensing plate is extremely small, and as the thickness of the isolated insulating panel increases, the size of the capacitance will exponentially decrease. After about 5mm of tempered glass, the touch of a human finger can only bring about a capacitance change of less than 0.5PF. For such a small measurement, changes in humidity, temperature, electromagnetic interference, power interference, etc. will greatly affect the measurement results of the measurement circuit. If there is no special and professional treatment method, it is difficult to ensure the stability of the touch-sensitive panel, especially the long-term stability under various harsh environments.
There are many companies that provide touch-sensing chips and solutions, and their levels are uneven. Companies with high technical level can solve the difficult problems of touch-sensitive panel design. The chips and solutions provided by some companies are well advertised and the things are cheaper, but the products can only guarantee "active". Without careful verification, it is difficult to ensure that customers will not have problems in various use environments.
After we have completed the design of a product with a touch-sensitive panel, we must use a relatively strict test method that is close to the customer's use environment to perform repeated and long-term tests to ensure the reliability of the product.