Virgil Joseph Hull

Print element for Xerox thermal ink-jet print cartridge

Xerox thermal ink jet print cartridges utilize a print element fabricated via VLSI technology. This fabrication process enables high productivity and precise dimensional control as well as the required electronic functionality. However, modifications to the device geometry involve a complex cycle of mask generation, VLSI fabrication, and assembly. The development of the print element is assisted by the use of experimental wafers which contain TIJ devices with variations in many important geometrical parameters. Analysis of data from measurements on these experimental geometries leads to designs.

Switching response of surface stabilized ferroelectric liquid crystal in a full-wave plate geometry

Abstract The optical transmission and response to an electric field of a surface stabilized ferroelectric liquid crystal (SSFLC) is frequently described for simplicity by a model which amounts to a rotation of a uniaxial crystal about the smectic layer normal. This model, though quite useful under most circumstances, neglects some interesting properties of the SSFLC. We have measured the optical properties of an SSFLC cell in the quiescent state and found it to deviate from the uniform birefringent slab model. When the thickness of the cell corresponds to a full-wave plate, an applied square-wave voltage reveals deviations in the form of scattering during the switching transitions.

Response time and contrast ratio of ferroelectric liquid crystal cells

The response time and contrast ratio of ferroelectric liquid crystals with positive and negative dielectric anisotropy were examined. The behavior observed after an isotropic anneal depended on the application of a high field. Before application, anomalous regions were observed which vanished after the application of a high field. Contrast ratio changes were observed, caused by the generation and annihilation of defects. Surfaces and structural changes appear to be involved in both the response-time and contrast-ratio behavior.<<ETX>>