Automotive AC Sensor FPC

As an experienced FPC factory in China, Honflex Electronics supports the development of smarter, more efficient, and energy-saving automotive AC systems.

Automotive AC Sensor FPC is a core segmented category of flexible printed circuits, specially used for signal transmission and connection of automotive air conditioning sensor systems, and is the "signal bridge" between air conditioning sensors and core components such as automotive electronic control unit (ECU), air conditioning host and display panel. As the "perceptual center" of the air conditioning system, automotive air conditioning sensors are responsible for collecting key data such as internal and external vehicle temperature, humidity, air conditioning pipeline pressure and air quality. The accuracy and stability of their signal transmission directly determine the temperature control accuracy, energy-saving effect and user experience of automotive air conditioning, and FPC, as the core carrier of signal transmission, directly affects the performance of sensor functions.

Compared with traditional rigid printed circuit boards (PCBs), Automotive AC Sensor FPC has the core advantages of bendability, foldability, thinness, light weight and dense wiring, which can accurately adapt to the narrow and special-shaped installation space of automotive air conditioning sensors (such as inside the instrument panel, air conditioning air outlets, pipeline interfaces, etc.), flexibly fit the sensor shell and complex internal assembly structure of the vehicle, effectively save installation space, simplify the assembly process of sensors, improve production efficiency, and reduce the overall weight of sensors, helping automobiles save energy and reduce consumption.

As one of the first enterprises in China to layout the flexible electronics industry, Honflex Electronics has become a core supplier in the field of Automotive AC Sensor FPC, serving many mainstream domestic and foreign automakers and automotive electronics Tier1 suppliers, relying on nearly 20 years of FPC R&D and production experience. The company's Automotive AC Sensor FPC products cover various types such as single-sided boards, double-sided boards, multi-layer boards and rigid-flex boards. According to the customer's air conditioning sensor design scheme and functional requirements, it can customize products of different specifications and performances, fully adapting to the needs of various air conditioning sensors of fuel vehicles and new energy vehicles (pure electric, hybrid), covering entry-level, mid-range, high-end and other full-scenario models, and realizing the "one-stop" flexible circuit solution supply from product design, sample proofing, mass production to after-sales service.

Key Technical Parameters

The key technical parameters of Honflex Electronics' Automotive AC Sensor FPC products strictly follow the automotive industry standards, balancing performance and practicality, and fully adapt to the signal transmission and installation needs of automotive air conditioning sensors. The parameters are optimized according to the characteristics of sensors such as humidity, high and low temperature, and strong electromagnetic interference. The parameters of products with different specifications can be customized according to customer needs. The core general parameters are as follows ):

Core Structural Characteristics

Based on the installation environment and functional requirements of automotive air conditioning sensors (needing to withstand alternating high and low temperatures, humid water vapor erosion, on-board vibration for a long time, and having extremely high requirements for signal transmission accuracy and stability), Honflex Electronics' Automotive AC Sensor FPC products have been targeted optimized in structural design, taking into account flexibility, reliability and signal accuracy. All structural designs have been repeatedly verified by Honflex Electronics' laboratory to adapt to long-term on-board use scenarios. The core structural characteristics are as follows:

1. Substrate Selection: High-end Flexible Substrate, Balancing Temperature Resistance and Moisture Resistance

The core substrate of the product adopts imported or domestic high-end polyimide (PI) substrate with a thickness range of 0.025mm-0.1mm. Compared with ordinary PI substrates, it has better flexibility, high temperature resistance, low temperature resistance, mechanical strength and insulation performance, and at the same time, the moisture-proof performance is focus optimized to adapt to the long-term use of automotive air conditioning sensors in humid environments. The PI substrate itself has good chemical corrosion resistance and weather resistance, which can effectively resist the erosion of water vapor, oil stains, dust, etc. in the on-board environment, avoiding substrate aging, embrittlement and cracking; its bending times can reach more than 100,000 times, and the minimum bending radius can reach 0.5mm, which can flexibly adapt to the narrow, special-shaped installation space and bending assembly needs of sensors, and will not cause substrate fracture or signal interruption due to long-term fitting or slight vibration.

In addition, the surface of the substrate has been specially passivated, which greatly improves the bonding force between the copper foil and the substrate, effectively avoiding problems such as copper foil falling off and delamination under on-board vibration and humid environment, and extending the service life of the product. Honflex Electronics selects high-quality substrate suppliers through a strict substrate procurement control system, establishes a supplier evaluation mechanism, and ensures that each batch of substrates meets the automotive industry ISO/TS 16949 quality system standard, ensuring product quality from the source.

2. Copper Foil Structure: Precision Copper Foil, Ensuring Signal Transmission Accuracy

Electrolytic copper foil or rolled copper foil is used, with a thickness range of 12μm-70μm, which can be flexibly selected according to the air conditioning sensor signal transmission needs (such as analog signals and digital signals of temperature, humidity, pressure, etc.). Among them, the FPC products of high-precision air conditioning sensors (such as air quality sensors, high-precision pressure sensors) for high-end models adopt rolled copper foil, which has finer grains, better conductivity and lower resistance, which can effectively reduce analog signal transmission loss, ensure that the data collected by the sensor is transmitted to the ECU in real time and accurately, avoid signal distortion, data deviation and other problems, and ensure the accuracy of air conditioning system temperature control and air quality adjustment; the FPC of basic air conditioning sensors (such as ordinary temperature and humidity sensors) for ordinary models adopts high-quality electrolytic copper foil, balancing performance and cost-effectiveness, meeting basic signal transmission needs.

The copper foil adopts the precision etching process independently developed by Honflex Electronics, and the minimum line width and line spacing can reach 0.03mm/0.03mm, which can realize a denser circuit layout, integrate more signal interfaces in a limited space, and adapt to the development trend of integration and multi-function of air conditioning sensors (such as integrating multi-parameter detection, signal amplification and other functions). Relying on advanced etching equipment, Honflex Electronics can ensure the precision and consistency of copper foil lines, with errors controlled within ±5μm, greatly improving the signal transmission stability and accuracy of products.

3. Cover Layer Design: Triple Protection, Enhancing Moisture and Temperature Resistance

Aiming at the core pain points of automotive air conditioning sensors being in humid environment with alternating high and low temperatures for a long time, the product surface is provided with three layers of protective structures, namely Cover Lay, Solder Mask and moisture-proof coating. The triple protection greatly improves the environmental adaptability and reliability of the product, ensuring that the product works stably in harsh environments. The cover film adopts a flexible PI cover film, which is accurately attached to the surface of the copper foil circuit to play the role of insulation, wear resistance, oxidation resistance and water vapor resistance, and does not affect the flexibility of the product, ensuring that the product can smoothly fit the special-shaped structure inside the sensor; the solder mask adopts high-end solder mask ink with high temperature resistance, wear resistance, chemical corrosion resistance and moisture resistance, which is printed on the surface of the cover film to further improve the product's resistance to high and low temperature impact, vibration, dust, water and moisture; the moisture-proof coating adopts special high-end moisture-proof materials, which are evenly applied on the surface of the solder mask to form a dense moisture-proof barrier, effectively blocking the invasion of water vapor and avoiding short circuit, signal interruption and other faults.

In addition, for the interface part of the sensor FPC (the part connected to the ECU, sensor chip and air conditioning host), a reinforcing plate design is adopted to improve the mechanical strength of the interface, avoid interface deformation and line breakage during plugging and unplugging, and ensure the stability of the connection. Honflex Electronics' cover layer lamination process adopts high-temperature lamination technology to ensure the close fit between the cover film, solder mask, moisture-proof coating and copper foil, substrate, without bubbles or peeling, further improving the reliability and moisture-proof performance of the product.

4. Special-shaped Structure Customization: Adapting to the Narrow Installation Space of Sensors

The installation space of automotive air conditioning sensors is extremely narrow, and the design schemes of sensors of different models and types are quite different, so the requirements for the shape, bending angle, size, thickness, etc. of FPC are different. Honflex Electronics has strong customization capabilities for special-shaped structures, and can customize special-shaped FPC products of different shapes, bending angles and sizes according to the sensor drawings, installation space dimensions and functional requirements provided by customers.

The product can realize multi-dimensional bending and folding, can accurately fit the installation position of the sensor shell, chip and interface, pass through narrow installation gaps, effectively utilize the idle space inside the sensor, simplify the overall assembly structure of the sensor, and reduce the assembly difficulty. At the same time, in the process of special-shaped structure design, Honflex Electronics' R&D team will conduct stress analysis and environmental adaptability testing, optimize the circuit layout and the structure of the bending part, avoid problems such as circuit crowding and stress concentration in the bending part, and ensure that the product will not be damaged due to bending fatigue and environmental erosion during long-term use. Up to now, the company has completed the customization of hundreds of special-shaped Automotive AC Sensor FPC products, adapting to the sensor design needs of different automakers, and accumulating rich customization experience.

5. Shielding Structure Design: Resisting Electromagnetic Interference, Ensuring Signal Purity

There are many electronic devices in the car (such as engine, radar, navigation, audio, etc.), which will generate a lot of electromagnetic interference. Most of the signals transmitted by automotive air conditioning sensors are weak analog signals, which are very vulnerable to electromagnetic interference, leading to signal distortion and data deviation, affecting the normal work of the air conditioning system. To solve this problem, Honflex Electronics has added a special shielding structure in the Automotive AC Sensor FPC products, using a shielding film or shield design to wrap the lines inside the shielding layer to form an effective electromagnetic shielding barrier.

The shielding structure can effectively resist electromagnetic interference in the on-board environment, prevent external electromagnetic signals from invading the lines, and at the same time avoid the electromagnetic signals generated by the FPC's own lines interfering with the normal operation of other electronic devices in the car, ensuring that the signals transmitted by the sensor are pure and stable, and improving the accuracy of signal transmission. The shielding layer is made of high conductivity materials, balancing flexibility and shielding effect, does not affect the bending assembly needs of the product, and has been specially treated to improve the bonding force with other structural layers, ensuring that there is no peeling or falling off during long-term use.

Main Performance Advantages

Relying on Honflex Electronics' R&D strength, advanced production technology and strict quality control, the company's Automotive AC Sensor FPC products are comprehensively superior to the industry average in performance. Aiming at the special use scenarios of automotive air conditioning sensors (humid, alternating high and low temperatures, strong electromagnetic interference, weak signals), it focuses on core advantages such as high signal accuracy, high environmental adaptability and high reliability, while taking into account lightweight, thinness and customization, as follows:

1. High Signal Accuracy, Ensuring Reliable Sensor Data Transmission

The core mission of Automotive AC Sensor FPC is to realize accurate signal transmission. Honflex Electronics has achieved extremely high signal transmission accuracy through optimized circuit design, adoption of high-end copper foil substrates and precision etching processes. The product has low signal transmission loss. At 1GHz frequency, the signal attenuation is ≤0.5dB/cm, which can effectively ensure the real-time and distortion-free transmission of weak analog signals such as temperature, humidity and pressure, ensure that the data collected by the sensor is accurately fed back to the ECU, and the error is controlled within ±1%, providing reliable support for the accurate temperature control and air quality adjustment of the air conditioning system, and avoiding problems such as large temperature control deviation and inaccurate air quality detection.

At the same time, the product adopts impedance matching design, and the impedance deviation is controlled within ±10%, which further improves the stability and consistency of signal transmission, ensuring that the signal transmission accuracy does not attenuate under different working conditions (high and low temperature, vibration); the added shielding structure effectively resists electromagnetic interference, avoids signal distortion, ensures signal purity, and comprehensively improves the working reliability of the sensor.

2. High Environmental Adaptability, Withstanding Harsh On-board Environment Tests

Automotive air conditioning sensors are in a humid environment with alternating high and low temperatures, dust and oil erosion for a long time, which has extremely high requirements for the environmental adaptability of FPC. Honflex Electronics' Automotive AC Sensor FPC has excellent environmental adaptability and can work stably in various harsh environments: the working temperature range is -40℃~150℃, which can work normally in extremely cold (such as northern winter, temperature as low as -40℃) and extremely hot (such as southern summer exposure, air conditioning pipeline temperature as high as 140℃ above) environments, without problems such as substrate embrittlement, line oxidation, and signal abnormality; the storage temperature range is -55℃~180℃, which can adapt to the storage and transportation environments in different regions, avoiding product damage caused by improper storage and transportation environment.

In terms of moisture resistance, it can work continuously for 2000 hours in an environment with relative humidity of 95% (40℃), with no obvious change in performance, and can resist the erosion of water vapor inside the air conditioning system, avoiding short circuit, delamination and other faults; in terms of chemical corrosion resistance, it can resist the erosion of on-board oil stains, air conditioning refrigerants, detergents and other chemical substances, and will not have problems such as substrate expansion and line short circuit; in addition, the product has waterproof and dustproof performance, passed the IP67 protection level test, which can effectively prevent dust and rainwater from entering the circuit, ensuring long-term stable operation of the product. Honflex Electronics conducts long-term aging tests on products by simulating different on-board outdoor environments to ensure that products can work stably in various harsh environments.

3. High Reliability, Adapting to Long-term and Frequent On-board Use Needs

The product has passed strict reliability tests, fully complying with the automotive industry ISO/TS 16949 quality system standard and AEC-Q200 (passive component reliability test standard), and can withstand various harsh tests in the on-board environment. The service life can reach more than 15 years, which is synchronized with the service life of the entire vehicle. The specific performance is as follows: in the vibration test, it can withstand the vibration environment of 10-2000Hz and acceleration of 10G, without line breakage or signal interruption, adapting to various vibration scenarios during vehicle driving (such as bumpy roads, engine vibration), avoiding abnormal sensor functions caused by vibration; in the impact test, it can withstand the impact force of 50G, which can resist the impact caused by sudden situations such as vehicle collision and emergency braking, ensuring that the product will not be damaged by impact.

In the fatigue test, it can achieve more than 100,000 repeated bendings, and the product performance has no obvious attenuation after bending, which can long-term adapt to the bending installation state of the sensor; in the lead-free soldering test, the soldered interface has high strength and stable conductivity, avoiding poor contact, signal interruption and other faults caused by poor soldering; in the humid aging test, after 2000 hours of humid environment test, the product can still maintain stable signal transmission and mechanical performance without any faults. Honflex Electronics has established a complete reliability test system, and each product must go through multiple rounds of reliability tests (vibration test, impact test, fatigue test, high and low temperature test, etc.) before leaving the factory, and unqualified products are resolutely not allowed to leave the factory to ensure stable product quality.

4. Lightweight and Thin, Helping Automobile Energy Saving and Consumption Reduction and Assembly Optimization

With the development of the automotive industry towards lightweight and energy-saving, the demand for lightweight on-board electronic components is becoming increasingly urgent. As one of the core on-board electronic components, the lightweight of automotive air conditioning sensors is of great significance to the overall energy saving and consumption reduction of the automobile and driving stability. Honflex Electronics' Automotive AC Sensor FPC products adopt thin substrate and precision structure design, and the overall thickness of the product can be controlled between 0.1mm-0.3mm. Compared with traditional rigid PCB, the weight is reduced by more than 60%, which can effectively reduce the overall weight of automotive air conditioning sensors, thereby reducing the overall weight of the automobile, helping the automobile save energy and reduce consumption (for every 10kg reduction in vehicle weight, the fuel consumption per 100 kilometers can be reduced by 0.05-0.1L).

At the same time, the thin and lightweight design can further save the internal space of the sensor, providing more possibilities for the miniaturization and integration design of the sensor. For example, it can realize the integrated design of multi-parameter sensors, improving the integration and sense of technology of the automotive air conditioning system; in addition, the lightweight design of the product can also reduce the vibration load during vehicle driving, reduce the loss of the product caused by vibration, further improve the service life and reliability of the product, and simplify the assembly process of the sensor, improving assembly efficiency. On the premise of ensuring product performance, Honflex Electronics continuously optimizes the product structure to maximize the lightweight and thinness of the product.

5. Strong Customization Capability, Adapting to Diversified Sensor Needs

The design schemes of automotive air conditioning systems of different automakers and models are quite different, and the types, functions and installation spaces of air conditioning sensors are also different (such as temperature sensors, humidity sensors, pressure sensors, air quality sensors, etc.), so the requirements for the specifications, performance, structure, etc. of FPC are different. Honflex Electronics has complete customized R&D and production capabilities, and can provide full-process customized services from product design, sample proofing, mass production to after-sales service according to the specific needs of customers.

Customers can customize FPC products of different specifications (line width and line spacing, thickness, size), different performances (signal transmission rate, environmental adaptability, bending life), and different structures (special-shaped, multi-layer, rigid-flex combination) according to the design needs of their own sensors; for high-precision, multi-parameter air conditioning sensors of high-end models, high-end FPC products with high-density lines, low signal loss and high reliability can be customized to meet the needs of high-definition data collection and multi-signal collaborative transmission; for basic air conditioning sensors of entry-level models, cost-effective FPC products can be customized to balance performance and cost. The company has a professional R&D and design team, which can quickly respond to customer needs, complete product design and simulation analysis. The sample proofing cycle is short (samples can be delivered in as fast as 3 days), and the mass production cycle can be controlled within 7-15 days, which can meet the customer's rapid mass production needs. Up to now, the company has provided customized Automotive AC Sensor FPC products for many mainstream domestic and foreign automakers, accumulating rich customized experience.

Application Scenarios

With excellent performance, strong customization capabilities and Honflex Electronics' brand strength, Honflex Electronics' Automotive AC Sensor FPC products are widely used in air conditioning sensor systems of various types of vehicles, including fuel vehicles and new energy vehicles (pure electric, hybrid), adapting to entry-level, mid-range, high-end and other full-scenario models, covering various types such as temperature sensors, humidity sensors, pressure sensors and air quality sensors. All application scenarios have achieved mass supply and have been highly recognized by customers. The specific application scenarios are as follows:

Automotive Air Conditioning Temperature Sensor

Automotive air conditioning temperature sensor is one of the core sensors of the air conditioning system, mainly used to collect temperature data inside the vehicle, outside the vehicle and air conditioning pipeline, providing a basis for the temperature control adjustment of the air conditioning system, and is widely used in the air conditioning systems of various fuel vehicles and new energy vehicles. This type of sensor has a narrow installation space (such as inside the instrument panel, air conditioning air outlet, evaporator surface), and is in an environment with alternating high and low temperatures for a long time, which has high requirements on the temperature resistance, flexibility and signal accuracy of FPC.

Aiming at the needs of air conditioning temperature sensors, Honflex Electronics has customized special FPC products, adopting high-end PI substrates and precision copper foil, optimizing the temperature-resistant structure and signal transmission design, ensuring the accurate transmission of temperature data with errors controlled within ±1%, and at the same time having excellent flexibility and high and low temperature resistance, which can adapt to the bending installation needs of narrow spaces and work stably in the range of -40℃~150℃. At present, the company's air conditioning temperature sensor FPC products have been mass-applied to sedans, SUVs, commercial vehicles and other models of many mainstream domestic and foreign automakers, and have been widely recognized by customers with stable