Product image for illustration purposes only.
The aging of infrastructure such as bridges and tunnels is a serious problem. And the need to improve safety continues to grow. Standardizing inspection quality and reducing management costs (labor costs and ease of installation) have become essential in ensuring the safety of infrastructure throughout the country. Epson is taking the approach of attempting to meet these needs through high-precision sensing technology that employs the company's accelerometers.
The movements and changes in large-scale infrastructure such as bridges and tunnels are infinitesimal, and thus difficult to grasp quickly and accurately. Signs that indicate deterioration of infrastructure may lie hidden among these infinitesimal changes, and capable and accurate sensors are needed to accurately detect these. But the mechanical servo accelerometers commonly used can be large, heavy, expensive, and not easy to handle. On the other hand, inexpensive and easy-to-handle silicon MEMS technology accelerometers have too much sensor noise to measure infinitesimal changes, leading to user dissatisfaction.
Accelerometers are sensors that detect acceleration. It is possible to calculate things such as the direction a body moves, the direction of gravity, inclination, vibrations,
shocks, speed, and displacement. For consumer use, they are equipped on devices such as mobile phones and portable game consoles where they detect user movements or are
utilized by the camera's display orientation adjustment function. In industrial applications, accelerometers serve a wide variety of purposes from measuring vibrations coming
from earthquakes or the environment, to health monitoring of bridges and other structures.
Epson's sensing solution technology is based on high-performance quartz sensor elements to which the company's proprietary microfabrication technology is applied. Epson accelerometers equipped with these high-performance quartz sensor elements feature the outstanding characteristics of low noise, high resolution, wide dynamic range and high stability.
The basic principle of the sensor entails finding acceleration by affixing a weight to a component serving as a spring, and measuring the displacement of this spring due to the acceleration that results from movement in the axial direction. There are various ways of measuring this displacement: from utilizing a piezoelectric element to detect the changes in voltage due to the piezoelectric effect, to utilizing a crystal unit to detect the changes in frequency due to tension.
Epson's accelerometers employ a dual tuning fork type quartz sensor element made using our own high-quality synthetic crystal material manufactured in-house.
By miniaturizing the dual tuning fork type crystal oscillator chip, and applying photolithography processing used in our semiconductor microfabrication technology, we were able to increase the CI value (a yardstick for crystal vibration losses) and overcome the miniaturization limit beyond which it is difficult to obtain good vibration characteristics. Moreover, using SoC developed specifically for industrial sensors, we created a compact, high precision accelerometer that greatly reduced peripheral equipment and electricity consumption, while maintaining performance. Here too, we leveraged Epson semiconductor technology to achieve miniaturization and low power consumption.
Because Epson accelerometers digitize the sensor quantities directly, no expensive analog conversion apparatus is required. High precision data can be processed with a computer as-is. In addition to providing resilience against external noise, high resolution, wide dynamic range, and high stability, we also offer items with a metal case to increase consistency through shielding, and items that feature waterproofing and dustproofing.
These compact, high-precision devices are suitable for use in harsh outdoor environments, and are ideal for use when you need to obtain high-precision data over a long period of time. Such uses include analysis and diagnosis of deterioration and damage in large-scale structures as part of structural health monitoring, measuring vibrations from earthquakes or the environment, and bridge displacement monitoring. Epson's accelerometer technology helps solve problems concerning the difficulty of practical use in infrastructure, and contributes toward the realization of a convenient, safe, and secure society.