In harsh environments such as high temperature and high humidity, the normal display and service life of digital tubes will be seriously challenged. To improve its reliability, a comprehensive plan should be formulated from multiple aspects such as materials, structure, and protection.
In high temperature environments, the plastic packaging materials, electrode leads, and phosphors inside the digital tube are prone to performance degradation. Selecting high-temperature resistant materials is the basis for improving reliability. The packaging shell can be made of high-performance engineering plastics such as polyetheretherketone (PEEK), which has excellent heat resistance and can work for a long time at a high temperature of 260°C. Compared with ordinary plastics, it can effectively avoid high-temperature deformation and cracking. For electrode leads, silver-plated or gold-plated copper alloy materials are used. This type of material not only has good electrical conductivity, but also has strong oxidation resistance at high temperatures, which can prevent poor contact caused by lead oxidation. For phosphors, rare earth phosphors with high temperature resistance are selected. Their luminous efficiency decays slowly in high temperature environments, which can ensure the stability of the digital tube display brightness.
High humidity environments can easily cause moisture inside the digital tube, causing short circuits or phosphor failure. Optimizing the structural design can effectively isolate moisture. A fully sealed packaging structure is adopted, and a silicone rubber sealing ring is used at the joint of the digital tube shell. The flatness of the sealing surface is ensured by a high-precision mold to achieve a good sealing effect. At the same time, moisture-proof fillers such as epoxy resin potting glue are filled inside the digital tube. This material forms a dense colloid after curing, which can not only prevent moisture from invading, but also provide mechanical support and buffering for internal components to avoid component damage caused by vibration. In addition, the pins are specially treated, a waterproof pin connector is used, and a waterproof coating is applied to the root of the pin to further enhance the moisture-proof ability.
The heat dissipation of the digital tube is very important in high-temperature environments. Reasonable heat dissipation design can reduce the internal temperature and extend the service life. A heat sink is installed on the back of the digital tube. The heat sink is made of aluminum alloy with high thermal conductivity. The heat dissipation is accelerated by increasing the heat dissipation area. For digital tubes with higher power, heat pipe heat dissipation technology can be used. The heat pipe can quickly transfer heat from the high-temperature area to the low-temperature area to improve the heat dissipation efficiency. At the same time, optimize the installation layout of the digital tube to ensure that there is enough air circulation space around it, cooperate with forced air cooling, use a small cooling fan to accelerate air flow, take away heat, and keep the working temperature of the digital tube within a reasonable range.
Harsh environment will affect the electrical performance of the digital tube, and targeted measures need to be taken. In the design of the drive circuit, select chips with a wide temperature operating range, such as industrial-grade drive chips, whose operating temperature range can reach -40℃ - 85℃, which can better adapt to high temperature environments than ordinary chips. Add overvoltage and overcurrent protection circuits. When the voltage and current fluctuate abnormally, the protection circuit will act quickly to prevent the digital tube from being damaged by electrical faults. In addition, the circuit board is specially treated and sprayed with three-proof paint to form a protective film on the surface of the circuit board to prevent moisture, salt spray, and mildew, ensuring stable operation of the circuit.
In an environment with high humidity and possible corrosive gases, the metal parts of the digital tube are easily corroded. The metal pins, frames and other parts of the digital tube are electroplated, such as nickel plating and chrome plating, to form a corrosion-resistant metal coating to isolate the direct contact between corrosive substances and metal. For the shell, a coating material with corrosion resistance, such as fluorocarbon coating, can be used. This coating is not only weather-resistant, but also has strong acid and alkali corrosion resistance, which can effectively protect the digital tube shell. Regular cleaning and maintenance of the digital tube to remove corrosive substances attached to the surface is also an important means to improve corrosion resistance.
To ensure the effectiveness of the reliability improvement plan, strict environmental adaptability tests are required. Simulate high temperature and high humidity environment, place the digital tube in a temperature and humidity test chamber, and work continuously for a certain period of time under high temperature (such as 80°C) and high humidity (humidity 95%) conditions to observe its display effect and electrical performance changes. Conduct a salt spray test to expose the digital tube to a salt spray environment to test its corrosion resistance. Through long-term aging tests, run continuously for hundreds of hours in harsh environments, record the failure of the digital tube, and optimize and improve the improvement plan based on the test results to ensure that the digital tube can operate stably and reliably in actual harsh environments.
Introduce intelligent technology to achieve real-time monitoring of the operating status of the digital tube. Install temperature and humidity sensors inside the digital tube to collect environmental parameters and its own working status data in real time, and send the data to the monitoring center through the wireless transmission module. When the temperature is too high, the humidity is too high or other abnormal conditions are detected, the system automatically alarms and prompts maintenance personnel to take measures. Use big data analysis technology to analyze the operating data of the digital tube, predict its service life and potential failures, and perform preventive maintenance in advance, further improving the reliability of the digital tube in harsh environments.
