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Rayleigh wave defect detection

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Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110067
EISBN: 978-1-62708-247-1
... shear waves can be excited up to the shear critical angle. When ϑ is increased further, reflectivity becomes unity. However, as mentioned above, energy propagating parallel to the surface is still possible. These are the waves that can lead to the excitation of surface acoustic waves (Rayleigh waves...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 April 2013
DOI: 10.31399/asm.tb.imub.t53720267
EISBN: 978-1-62708-305-8
... it is particularly viscous or is present as a very thin layer. Surface Waves Surface waves (Rayleigh waves) are another type of ultrasonic waves used in the inspection of metals. These waves travel along the flat and curved surfaces of relatively thick solid parts. For propagation of waves of this type...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110209
EISBN: 978-1-62708-247-1
... resolution and wavelength as given by Lord Rayleigh’s criteria can be written [6] Resolution =  0 .61 ⋅ λ N .A . where λ is the wavelength of light being imaged and N.A. is the numerical aperture of the microscope. This result provides a good estimate of the resolving power...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110042
EISBN: 978-1-62708-247-1
... of resolution is the Sparrow Criteria, given as the just resolvable separation between two point sources as shown in figure 10 . The relation between the Sparrow Criteria and the somewhat better known Rayleigh Criteria is also shown. Equation 3 Rayleigh Criteria Sparrow Criteria D...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110244
EISBN: 978-1-62708-247-1
... can be determined by the Rayleigh criterion: Δ x , y = 0.61 λ N A where Δ x, y is the minimum resolvable lateral distance, λ is the wavelength of the laser, and NA is the numerical aperture of the optical system. This shows that in addition to increasing the NA (which...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110180
EISBN: 978-1-62708-247-1
... (eq. 1) R = r λ N A with the wavelength λ, NA the numerical aperture of the objective and the Rayleigh criterion r = 0.61. For air gap objectives, NA is the sine of the objective opening angle, necessarily a little smaller than 1. A rough approximation of R is λ/2 as used by Abbe’s...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110351
EISBN: 978-1-62708-247-1
... of IR based imaging is fundamental based on the Rayleigh criterion of resolution R for a given wavelength R(λ)= ~λ/2NA. Figure 3 shows a high contrast image of an IC through 10 µm of remaining silicon substrate thickness [15] . This sample was illuminated using an 880 nm LED as a light source...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2019
DOI: 10.31399/asm.tb.mfadr7.t91110153
EISBN: 978-1-62708-247-1
... spaced objectives. The increase is shown in Figure 25 for both the Rayleigh and Sparrow criteria. The relationship clearly shows increasing resolution as wavelength decreases and/or Numerical Aperture (NA) increases. Figure 23 SIL in optical contact with the wafer gives a huge benefit...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 1984
DOI: 10.31399/asm.tb.mpp.9781627082600
EISBN: 978-1-62708-260-0
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 1984
DOI: 10.31399/asm.tb.mpp.t67850060
EISBN: 978-1-62708-260-0
... Abstract This chapter explains how to prepare metallographic samples for light microscopy and how to anticipate and avoid related problems. It describes standard practices and procedures for sectioning, mounting, grinding, and polishing and identifies common defects along with their causes...