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Doubly Rotated Blanks

This document provides typical specifications for Doubly Rotated Blanks - single crystal cultured quartz blanks fabricated with a double angular rotation suitable for operation in the thickness shear mode. This family of blanks includes the SC-cut and IT-cut and is designed to reduce the effects of stress on resonant frequency.

Section Drawing
Doubly Rotated Blanks Section Drawing

Doubly rotated blanks can be fabricated to a range of specifications for either of the two angles of rotation as well as the overall blank dimensions. Typical specifications for the j -rotation (i.e. the first, or X to X', rotation) are around 22° for SC-cut blanks and 19° for IT-cuts, but can vary by as much as ±10. The q -rotation (i.e. the second, or Z to Z' rotation) typically ranges from 33° to 35°. Verification of specified orientation is assured by providing us with the appropriate x-ray diffraction reference standards. As the blanks are usually angle corrected after delivery, both surfaces are lapped to a rough finish using 15 µm abrasive, unless otherwise specified.

 

Mechanical Characteristics

Units  
Typical Values
Tolerance
X-height x Z-width
mm
16.5 x 16.5
± 0.25
Thickness, t  
As specified
± 0.013
Orientation - φ
degrees
As specified (18°-24°)
± 10 minutes
Orientation - θ
degrees
As specified (33±-35°)
± 5 minutes
Standard dimensions (other dimensions are available to meet customer-specific requirements)

 

 

Material Characteristics

Handedness
Right
      
Infrared a (3500 cm-1)
α - units
Grade B: 0.045
maximum
     
Grade l
 
Inclusions (diameter)
25 - 75 µm
cm3
4
  
 
75 - 100 µm
cm3
2
  
 
>100 µm
cm3
2
  
Etch Channels
cm2
Grade 4: 300
maximum
Twins in useful volume
Count
None
  

 

Surface Characteristics

Seed Characteristics

Pure - Z, seed free material

References

International Electrotechnical Commission Standard, CEI/IEC 758, Second edition, 1994.

Institute of Electrical and Electronic Engineers Standard on Piezoelectricity, ANSI/IEEE Std. 176-1 987.

 

 

 

Reproduced by kind permission of Sawyer Research Products, Inc.© Sawyer Research Products, Inc. Specifications subject to change without notice.All rights reserved

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