Metallic Thin Film Sensors Special Feature

Chapter 1
Introduction

In this feature, we will showcase our commitment to the development of metallic thin film sensors.
Leveraging our refined proprietary sensing technologies, we contribute to the creation of innovative products in various fields by harnessing the high-performance potential generated by this technology.

Types of Strain Sensors

First, let's briefly explain strain sensors. Even rigid objects deform slightly when subjected to force. Strain sensors can detect these imperceptible deformations (strain), allowing us to estimate the stress within objects that are causing the strain. Strain sensors are classified into resistance foil strain sensors, semiconductor strain sensors, and thin film strain sensors.

(1) Resistance Foil Strain Sensor

When a metal foil, which serves as a resistive element, is subjected to stress, it stretches and changes in both cross-sectional area and length, causing a change in resistance value. Strain is measured by extracting this change in potential.

(2) Semiconductor (Si-MEMS) Strain Sensor

Stress on a semiconductor element exhibits piezoresistive effects, resulting in a change in resistance. While semiconductor strain sensors offer high sensitivity due to the piezoresistive effects, they are also sensitive to environmental changes like temperature.

(3) Thin Film Strain Sensor

These sensors are made by forming a thin film with piezoresistive properties on a substrate. They exhibit characteristics that are intermediate between resistance foil and semiconductor strain sensors.

What is a Thin Film Strain Sensor?

Thin film sensors use metal materials with piezoresistive properties on the strain sensor film and deposit the film on the substrate using methods such as sputtering. When the substrate is an insulator like ceramics, the strain sensor material can be directly deposited on the substrate. However, when the substrate is metal, an insulating layer is required to prevent electrical contact between the substrate and the sensor material.

Like other strain sensor types, the change in resistance due to strain is minimal compared to the original resistance value. To extract this change, a Wheatstone bridge circuit is used to measure the difference in potential from the balance point.

The strain sensors we introduce here fall into category (3), the thin film strain sensor. It's worth noting that many strain sensors attach resistive foils or semiconductor elements onto resin films or have thin film elements formed on films, while our thin film strain sensors are mounted on rigid metal chips.

Chapter 2
Strengths of Our Metallic Thin Film SensorsOur strong points

In this section, we will introduce the high-performance and unique features of our developed metallic thin film sensors.

Pursuing High Performance Potential and Convenience

High Potential and Convenience

Thin-film strain gauge cad_Nidec Components

Our metallic thin film sensors strike a balance between sensitivity and environmental stability, providing high potential for various measurement needs. These sensors employ highly sensitive thin film materials and directly detect stress in the substrate through an insulating layer, resulting in outstanding performance.

1. High Sensitivity

Our thin film materials have a gauge factor 5 to 10 times higher than typical metal foils. This high gauge factor allows us to achieve a high signal-to-noise ratio and enables high-sensitivity sensing for strain.

2. Excellent Linearity

Our strain sensor elements are strongly bonded to the substrate via a rigid insulating layer, reducing the occurrence of hysteresis since there are no intervening sliding factors.

Even within the linear elastic range of metals, our high-sensitivity strain sensor elements can detect slight strains, ensuring high linearity.

3. Low Drift

Traditional film-type strain gauges have adhesive or resin materials between the strain gauge element and the substrate. Over time, environmental influences may cause these materials to deform, leading to drift. In contrast, our sensors are directly deposited on metal substrates, avoiding deformation of materials and making them less susceptible to environmental and temporal changes, resulting in reduced output drift.

4. High-Speed Response

With minimal substances between the sensor and the substrate due to the direct deposition structure, inhibiting factors for response are minimized. As a result, the transmission speed from deformation is extremely fast, allowing for quick and accurate measurement of force and torque fluctuations.

5. High Durability

Our direct deposition structure offers exceptionally high durability. Even after 10 million cycles of durability testing, the performance remains unchanged.

6. Easy Installation

Our thin film strain sensors, which are directly deposited on metal chips, are mounted on the test object using a "screw-fastening" joining technique. This method allows for flexible structural design tailored to the device being installed, eliminating the need for time-consuming adhesion to the test object, making it suitable for mass production. This approach provides excellent stability and accurate strain measurement.

7. Design Flexibility

The gauge pattern is achieved through the deposition process, allowing for pinpoint and fine patterns to be formed at the point of strain, making it possible to configure the thin film strain sensor according to the strain occurring in the customer's test object and enabling free design.

Providing Sensor Chips as Sensor Modules for Structures

To leverage the high performance of our metal thin film sensors and offer cost-effective and highly manufacturable force/torque sensors, we have developed and scaled our technology for attaching standard sensor chips to the test object.
By designing the elastic structure for attaching the sensor chip in the most suitable shape, we can achieve affordable force and torque sensors for a wide range of purposes, from heavy loads to microforces.

Elastic structure shape based on the measured load

※Please note that we provide sensor-chip-attached structures as sensor modules and do not offer sensor chips separately.
and do not offer sensor chips separately.

[Integrated Circuits avilable too]

We also offer integrated circuits that include voltage supply to strain sensor elements, amplification of the detected potential difference, A/D conversion, calibration, serial communication, and other functions. These standard circuits can be provided as integrated sensor modules.

Please contact us for information on standard interfaces (standard is RS485, but also others such as RS422, EtherCAT, etc. available).
※Please contact us for information on standard interfaces (standard is
RS485, but also others such as RS422, EtherCAT, etc. available).

Chapter 3
What Can Be Achieved with Thin Film SensorsWhat can be done with it?

Diverse Functional Possibilities

Our metallic thin film sensors can be used to achieve various functional needs. For example, you can:

Measure the magnitude of forces or torques applied in one direction, ranging from very small forces to heavy load such as ton-class.

Measure the magnitude of forces or torques applied in multiple directions, separately measuring each axis.

Precisely control pressurized forces or rotational torques according to measured load.

Measure varying loads to detect anomalies or estimate lifespan.

Precisely weigh and measure weight or tension.

Instantly detect minimal movements.

Convey the applied force to a person in a realistic way.

Control equipment based on the amount of applied force.

Please Share Your Requirements and ApplicationsIdeas and Uses

By using our thin metal film strain sensors on metal substrates, it is possible to meet a variety of functional needs, such as the following:

Robotics,
Co-robots
Power Assist
Touch Probes
Catheters
Machine Tooling
Load Cells
Weighing Scales
Press Molds
Sewing Machines
Input Devices
Joystick
Controllers
Torque Control
for Mobility

From the above, our metallic thin film sensors are suitable for a wide range of applications.
To provide you with sensors that best suit your application's performance and usability, we propose sensors tailored to your specific needs. Effective collaboration in the early stages of development, including technical and specification alignment, is essential to deliver the sensor that best matches your product. Please feel free to consult with us.