Sensors&Printed Electronics

Thin film pressure sensors are sensors based on thin film materials, and their main function is to measure the pressure applied by an object on its surface. They are usually composed of a thin film, a base, and a conductive layer, and their working principle is based on the change in resistance of the thin film material when it is subjected to force. In short, thin film pressure sensors are flexible and versatile sensors that are suitable for a variety of different application scenarios, thus providing solutions for pressure measurement and touch detection.

Working Principle The working principle of thin film pressure sensors is based on the change in the electrical potential of thin film materials when they are subjected to force. These sensors are usually composed of a thin film, a conductive layer, and a supporting base. The following is an overview of the basic working principle of thin film pressure sensors:

• Film material: The thin film in the sensor is usually a flexible, conductive material, such as polyester film or polymer film. These materials are elastic and can undergo small deformations when subjected to external pressure.
• Conductive layer: The film is covered with a conductive layer, usually metal or conductive ink. The resistance of this layer is directly related to the pressure of the external environment.
• Change in electrical potential: When pressure is applied, the film undergoes a small deformation, causing the electrical potential of the conductive layer to change. This is because the resistance is related to factors such as the length and width of the conductive layer and the distance between the conductive layers.
• Measurement of electrical potential: By measuring the change in resistance value, the sensor can determine the level of pressure applied to its surface. Generally, the resistance value increases with increasing pressure, reflecting the deformation of the film when it is subjected to force.
• Signal processing: The change in electrical potential output by the sensor can be interpreted and converted by signal processing circuits to produce a voltage or digital signal related to the pressure. This signal can be connected to a microcontroller or other electronic device for further data processing or control applications.

Application characteristics

Thin film sensors provide information about pressure levels by monitoring the tiny deformation of thin film materials when they are subjected to force, which is converted into changes in resistance. Here are some of the main applications of thin film pressure sensors:

1. Touch sensing: can be used to detect and measure touch and press. This application is common in devices such as touch screens, electronic keyboards, digital buttons, etc.

2. Force measurement: can measure the amount of force applied to the surface of an object. In industrial, manufacturing and laboratory environments, they can be used to monitor the force on machines and equipment and trigger corresponding actions when needed.

3. Medical equipment: widely used in the medical field, such as making wearable devices, bed monitoring systems or other medical devices to measure the pressure distribution, posture and movement of patients.

4. Automotive industry: In automotive manufacturing, thin film pressure sensors are used to monitor the position and weight distribution of passengers on seats to better control the deployment of airbags.

5. Industrial automation: In industrial environments, these sensors can be used to monitor the pressure, force or touch status of equipment to achieve automated control and monitoring of production processes.

6. Robotics: can be used for touch perception of robot hands or fingers, allowing robots to interact with the surrounding environment more sensitively.

Soft Circuit Membrane Switch

Soft circuits can be developed using polyester or polyimide as the base material, depending on your interface requirements. From simple single layer copper flex on polyester to complex double-sided on polyimide, rapidly provides customers with application-specific solutions.

Trace Width

Standard line width-0.25mm, minimum 0.10mm

Standard trace pitch-0.50mm, minimum 0.20mm

Minimum space between-circuits 0.10mm

Plating

Tin-lead, nickel, gold

Component Assembly

Connector crimping

Soldering of components

Base Material

Polyimide: standard thickness-1mil 2mil and 1/2 mil available

Polyester: standard thickness-3mil 1mil, 2mil and 5mil available

Conductor: laminated ED copper or RA copper-standard thickness 1 oz (1.4mil/0.035mm) 1/2 oz and 2 oz available

Coverlay: polyimide, polyester or solder mask thickness-1/2 mil, 1mil, 2mil, 3mil or 5mi