Recent developments in temperature

measurement have encouraged

researchers to develop

low-cost

simple structure

computerized generic transducers for

environmental monitoring

industrial process control.

Acoustic

Temperature

Transducer

QUITEVIS, Mary Francis(Enguero)

Agenda

Definition

Principle

Sensor Technology

Application

ATT?

Device based on the

characteristics of sound waves

in a wave- guided media, in

which sound wave is guided

physically

Basic Principle

Speed of sound is proportional to the

absolute temperature, which is also

related to the frequency of the sound

wave, assuming existence of a constant

wavelength.

C = f . λ

v = 331m/s + 0.6m/s/C * T

Speed of

Sound

358.0 m/s

343.6 m/s

330.4 m/s

Status Quo:

Problem?

Predominant market need for sensors that are

competitively priced due to mature and established manufacturing methodologies

inherently rugged because of the implementation of advanced packaging techniques

very sensitive and intrinsically reliable.

Greater Problem?

Sensors need to be of a very small size, not influenced by magnetic fields,

contribute to emerging market needs of being able to support data

monitoring functions wirelessly

complementing additional functionalities such as low power requirements

being passively and wirelessly interrogated (no sensor power source required).

Solution:

ATT

Ability to fulfill the above market requirements

high performance

small size

high reproducibility

Fig. 1. ( а ) Diagram of the experimental setup for detecting

heated bodies placed in biological media; (b) result of

detection of the heated body placed in gelatine.

Distinction

The acoustic temperature sensor

provides temperature measurement

that is independent of wafer

emissivity conditions and lamp

radiation levels.

It does not require thermal contacts

on the wafer and is compatible with

the reactive conditions of rapid

thermal processing.

Fig. 2. Two-dimensional tomogram of a heated sample placed in

water. The tomogram was obtained by antenna focus scanning

in depth and along the transverse coordinate.

Importance of

Acoustic Techniques

Used to monitor the temperature of silicon wafers during rapid thermal processing from room temperature to 1000 C with tolerance 5 C accuracy.

Acoustic transducers are mounted at the bases of the quartz pins that hold up the silicon wafer during rapid thermal processing.

Security System

Ability to detect the range of the person

way from the sensor

Effective monitoring system enabling the

knowledge of a moving body’s

prescence

Telecommunications

Industry

Largest volume application -

accounting for filters and

oscillators in mobile cell phones

and base stations.

SAW?

Surface acoustic wave devices and

Function as band-pass filters in both the

radio frequency and intermediate

frequency sections of the transceiver

electronics..

Applications

Automotive applications (tire pressure and oil condition monitoring sensors) and industrial and commercial applications (temperature in ovens, pressure in tanks).

References

http://www.directindustry.com/prod/dytra

n-instruments/acoustic-sensors-37504-

342307.html

http://www.processindustryinformer.com

/Editorial-Feature-Archive/WIRELESS-

TEMPERATURE-SENSING-BY-

ACOUSTIC-WAVE-SENSORS

http://www.sensorsportal.com/HTML/DI

GEST/august_2010/P_656.pdf