Downloaded 698 times
More Related Content
Similar to Surface acoustic wave technology
Surface acoustic wave technology
- 1. Surface Acoustic Wave Technology PresentedBy: AKHIL BARAIK
- 2. Outline • Introduction • Terminology •Surface Acoustic Wave(SAW) - Components - Properties • SAW Principle • Applications • Advantages & Disadvantages • Conclusion • References Outline
- 3. Outline Surface Acoustic WaveTechnology Brief History: • Surface Acoustic Waves (SAW) were discovered in 1885 by Lord Rayleigh • SAW device was invented by White and Voltmer in 1965 • Around 1970, developed for Pulse Compression Radar, oscillators, and bandpass filters for domestic TV • Diverse applications in consumer and highly professional electronic devices and systems • Perform different functions in the frequency range from 10 MHz to several GHz. Introduction
- 4. Outline Continued... Terminology • Surface: Outsidepart or uppermost layer of something. • Acoustic : Science deals with the study of all mechanical waves in gases, liquids, and solids. • Wave: Oscillation accompanied by transfer of energy that travels through space or mass. • Acoustic Wave : Type of longitudinal wave propagates by means of adiabatic compression and decompression. Introduction
- 5. Outline Definition • A SurfaceAcoustic Wave (SAW) is an Acoustic Wave traveling along the surface of an elastic substrate. • Frequency of SAW: F=V/ λ V=Velocity of SAW (~ 2500m/s-10000m/s) λ=wavelength • Type of mechanical wave motion travels along the surface of solid material. Surface Acoustic Wave(SAW)
- 6. Outline SAW Device . Fig :Basic Structure of SAW Device Surface Acoustic Wave(SAW)
- 7. Outline Continued... SAW Device? • Asolid state device – Converts electrical energy into a mechanical wave(Acoustic) on a single crystal substrate and vice versa – Provides very complex signal processing in a very small volume • Approximately 4-5 billion SAW devices are produced each year Surface Acoustic Wave(SAW)
- 8. Outline SAW Device Components •Transducers(IDT) • Piezoelectric Substrate – Crystal Quartz(SiO2) – Lithium Niobates(LiNbO3) – Lithium Tantalates(LiTaO3) etc. • Reflectors Surface Acoustic Wave(SAW) Fig : Typical Piezoelectric Transducer Fig : SAW Reflector Gratings
- 9. Outline SAW Properties • PiezoelectricSubstrate : Acoustoelectric Conversion • Small Surface Perturbation: 0.1-20 A0 • Velocity: ~2,500 -10,000 m/s • Efficient Transduction • Frequency Range: ~10MHz to 3GHz Surface Acoustic Wave(SAW)
- 10. Outline SAW Comparison withEM wave Vsaw=~3000 m/s Vem=~3 x108 m/s F λ=V Surface Acoustic Wave(SAW) F=10MHz F=1GHz λsaw 300 µm 3µm λ EM 30m 3m
- 11. Outline SAW Principle • Basedon Piezoelectric Effect: Useful in applications: – production and detection of sound – generation of high voltages etc • Based on Acoustic Wave : Wave propagates by means of adiabatic compression and decompression. SAW Fundamentals
- 12. Outline Continued... Piezoelectric Effect •Also called as Piezoelectricity • The ability of certain materials to generate an voltage when subjected to mechanical stress • Reverse is also true. SAW Fundamentals Fig : Piezoelectric Effect
- 13. Outline • SAW TouchScreen • SAW Filter • Delay Line • Resonator • Sensors • RFID Applications
- 14. Outline SAW Touch Screen Application •Anelectronic visual display locates the coordinates of users touch within display area •Works independently of what is being displayed on screen
- 15. Outline Continued... SAW Based TouchScreen Application
- 16. Outline Continued... SAW Touch Screen •Surface consists of glass overlay with transmitting and receiving transducers • Electrical signals sent to the transmitting transducers • Waves are directed across screen by reflectors then directed to receiving transducers Application
- 17. Outline Continued... SAW Touch Screen •When finger touches screen it absorbs waves • Received values are compared to stored digital maps to calculate x and y coordinates Application
- 18.
- 19. Outline Application of SAWTouch Screen • ATMs • Amusement Parks • Gaming Environments • kiosks • Industrial Control Rooms Application
- 20. Outline Why SAW TouchScreen? • Advantages: – Best optical quality – High surface durability – Activated by multiple sources – High “touch-life” • Disadvantages: – Expensive – Contaminates on screen can cause false-touches – Non conductive material can not activate screen Application
- 21. Outline Surface Acoustic Wave ADVANTAGES: •Low Velocity • Low attenuation • Low cost • Simple design and fabrication • Low power consumption DISADVANTAGES: • Can not be operated in liquids • Piezoelectric substrates are temperature dependent ADVANTAGES & DISADVANTAGES
- 22. OutlineCONCLUSION • Surface AcousticWave Technology is widely used technology. • Applied to design filters, different sensors, resonators, delay lines and many commercial devices. • Most emerging technology across the world. • All the electronics equipments and devices use SAW technology. • The demand of SAW technology will never abate because of its fruitful advantages than disadvantages.
- 24. Works Cited http://en.wikipedia.org/wiki/Surface_Acoustic_wave http://www.dmccoltd.com/english/museum/touchscreens/technologies/AcousticWave.asp http://www.elotouch.com/technologies/intellitouch/default.asp http://admetro.com/products/surface-acoustic-wave-saw http://www.baanto.com/surface-acoustic-wave-saw-touch-screen http://www.analog.com/library/analogDialogue/archives/44-02/touch_screen.html http://apcmag.com/inside-touch-how-touchscreen-technologies-work.html http://www.slideshare.net/mshirif/touch-screen-technologies# http://computer.howstuffworks.com/question716.htm