Quartz blanks
Quartz blanks are thin plates, with diameter from 4.0 up to 20 mm or even more, made from quartz crystal. Blank surface can be fine lapped, chemically etched or polished. The
cut angles mostly used are: family of AT-cuts, BT-cut, CT-cut, DT-cut,
X-cut and Y-cut. They are used for production of quartz crystal units,
quartz crystal filters, piezoelectric transducers and for other
applications.
They can be delivered as unplated or plated with metal electrodes. The thickness of blanks can be from 0.040 up to 1.0 mm or more. For AT, BT, X and Y cuts the thickness can be specified by resonant frequency and tolerance. The blanks shape can be plan-parallel (unbevelled or bevelled ), plan-convex or bi-convex with customer specified radius of convex-surface.
They can be delivered as unplated or plated with metal electrodes. The thickness of blanks can be from 0.040 up to 1.0 mm or more. For AT, BT, X and Y cuts the thickness can be specified by resonant frequency and tolerance. The blanks shape can be plan-parallel (unbevelled or bevelled ), plan-convex or bi-convex with customer specified radius of convex-surface.
Typical parameters of Quartz Blanks
| Parameter | Minimal |
Maximal |
| Diameter [ mm ] | 4.0 ± 0.02 | 20.0 ± 0.02 |
| Thickness [ mm ] | 0.04 ± 0.001 |
1.0 or more |
| Cut angle tolerance | ± 15" ( for AT-cut ) | ± 30' |
| Surface roughness | polished | customer specified |
| X-axis marking | for Y-rotated cuts by small flat or customer specified | |
In customer specification of quartz blanks should be specified:
- Diameter with tolerance
- Cut with tolerance
- Thickness or frequency with tolerance
- Surface roughness ( Ra in mm, or No. of lapping grain size )
- X-axis marking ( for Y-rotated cuts )
- Blank shape ( plan-parallel, plan-parallel bevelled, plan-convex, or bi-convex )
- For plated blanks specification of electrodes
Synthetic Quartz material specification ( according EN/IEC 60758:2004, Ed.3 ):
- Quality grade: Grade C ( standard ), Grade B, Grade A ( according customer specif.)
- Inclusion density: Grade Ib ( standard ) or better ( according customer specification )
- Etch channel density: Grade 3 ( standard ) or better ( according customer specification )
Shapes of quartz blank
Typical outline dimensions of AT-quartz blank
