TBA Series
Fast, accurate and reproducible evaluation of Tilt Bias Angle
Fast, accurate and reproducible evaluation of the Tilt Bias Angle (TBA, pre-tilt angle) as induced by the alignment layers of LCDs is of crucial importance in Research and Development, product optimization as well as in manufacturing control. The TBA angle can also be used as a probe to monitor the reproducibility of the rubbing process.
Based on the variation of the angle of light incidence (crystal rotation method) the TBA measurement systems have overcome all initial limitations and drawbacks of that method.
Our unique algorithms for TBA evaluation offer the following advantages:
- no simplifying assumptions required (e.g. "symmetry offset angle"),
- evaluation of thin and twisted LC-layers possible,
- no adverse effect of Fabry-Perot interferences,
- covering the full range from planar to homeotropic LC alignment,
- simultaneous evaluation of TBA and cell gap,
- input of only ne and no required,
- automatic determination of zero orientation of test-cell,
- temperature controlled (heated) test-cell fixture for evaluation of TBA variations with temperature,
- small measuring spot size for area scanning and evaluation of lateral TBA uniformity.
Operation of the TBA measuring systems is easy and convenient due to automatic zero adjustment and due to the transparent structure of the TBA WORKBENCH software.
The TBA 107 is a compact solution for small test-cells (up to 100 x 100 mm), the TBA 110 is optimized for large test cells (up to 42" diagonal) with realistic cell-gap (down to 4 μm) , as they can be sampled directly from the manufacturing line. The TBA 110 can optionally be provided with a heating and a scanning stage, thus allowing automated measurement and evaluation of temperature induced TBA variation and lateral TBA uniformity. Color filters inside the cells under measurment do not negatively affect the TBA evaluation algorithm.
