In the liquid crystal display industry, there are many components that depend on homogeneous birefringence characteristics in order to produce the best image. At this time, the most expensive component for LCDs is the thin glass substrate made of fused silica.

Birefringence in the glass is indicative of stress. Stress can cause the substrate to twist or bend, leading to misalignment and a poor product. There are many layers that make a LCD and these layers must mesh with extremely tight tolerances. If the birefringence characteristics are low and homogeneous, the components will be easier to align when stacked on top of one another.

Exicor systems can measure accurately with high repeatability to the best specification of any system in the world: .005nm. The fused silica built by glass manufacturers is very thin and unstable with temperature fluctuation and stress. Exicor can measure these ultra-low retardation levels, providing QA and QC groups with the concrete data they need to serve their customers.

Exicor reference samples are also a key part of this application. Since we are working at extremely low retardation levels it is necessary to have a reference sample that will be stable and homogeneous in the sub-nm range.

How Exicor has assisted customers:

• LCD glass is thin with very low birefringence. Only Exicor delivers repeatability to .005nm to ensure accurate measurement.
• Exicor "Maximum view" stages provide a stable fixture with a large viewing area.
• Exicor reference samples ensure performance specifications are met over time and permit testing to ensure repeatability between systems.

For this application, we recommend the use of the following systems:

For smaller samples, the Exicor 150AT  is suggested.
For larger samples, the Exicor 1500AT is suggested.
Custom applications will require the Exicor MT
We recommend use of an Ultra-low birefringence reference sample.